WiFi extender

Trying to decide which WiFi extender to use can be very difficult. There are a lot of very confusing fact pertaining to the hardware to extend a WiFi signal. Even determining the need to extend your WiFi network can be a matter a guesswork. There are plenty of manufactures offering all types of equipment which promise everything from increasing the speed of your network to improving the range of your router or modem. We have done some research on this issue because the TV2 monitor should plugged into your LAN for you to take advantage of all the features of the TV2 system.

The TV2 monitor is equipped with an Ethernet socket so it can be plugged into a switch or hub on a Local Area Network. Once the TV2 is plugged into the LAN it receives an IP address from the DHCP on the same LAN. The free secure software that is provided with each TV2 can be installed on any computer on the LAN and the TV2’s IP address entered. Once that is done the TView software can be used to download the logged data from the TV2 monitor. Additionally the software can be used to automatically backup all data from the TV2’s sensors to a PC. And text and email alerts can be sent vie the LAN’s internet connection. Lastly the current conditions can be displayed on PCs.

These functions of the TView software greatly increases the functionality of the TV2. However we do have users who do not have wired Ethernet drops close to where the TV2 is deployed. One option for this situation is to employ a wired to wireless converter – what is commonly called a bridge. The TV2 can be plugged into the bridge which is linked to the LAN with its WiFi connection. All types of bridges are available and it can be very difficult to determine what piece of hardware will best suite the needs in any given situation. This article offers very good information as well as guidance to which piece of hardware will work best in which applications.

There is another alternative available and that is to purchase the TV2 with a WiFi connection. This completely eliminates the need or a bridge although you may still need an extender if the area where the TV2 is to be positioned is too far away from a WiFi access point. The above referenced article can point you in the right direction.

Negative Pressure Room

What is a negative pressure room

A negative pressure room, also known as a “negative pressure isolation room” is a controlled, critical area, which maintains a negative pressure differential to a non-controlled space. The need for such controlled spaces has increased dramatically in light of the COVID-19 pandemic. Most U.S. hospitals use negative-pressure airborne infection isolation rooms (AIIRs) to house patients with suspected or confirmed airborne transmissible infections such as COVID-19. When a patient is positively diagnosed, they are typically isolated in a room which maintains negative pressure at all times. This protects the general public, hospital/healthcare workers, and others from cross-contamination.

A negative pressure isolation room is monitored constantly for negative pressure. This measurement is usually on a “pascal” scale (Pa) or may also be measured in “inches of water column” (WC). In a negative pressure room, the air pressure is lower than adjacent spaces, or “negative.” This simply means that when the door of a isolation room is opened, air is sucked in to the room, instead of being pushed out. This forces all airborne pathogens, particulates and microbial contaminants to remain in the isolation room and not escape into generally populated areas.

On the opposite end of things, a positive pressure room pushes air out when a door or window is opened. These positive pressure areas are ideal for cleanrooms where the highest level of cleanliness is required for pharmaceutical manufacturing, surgical rooms, technology manufacturing, sterile manufacturing, etc. In the case of a positive pressure room, all air is pushed out, thereby preventing outside contaminants from entering.

There are four types of isolation rooms, two of which are negative pressure rooms.

  • Neutral or standard room air pressure, for example standard air conditioning, also known as Class S
  • Positive room air pressure where an immune-compromised patient is protected from airborne transmission of any infection, Class P
  • Negative room air pressure, where others are protected from any airborne transmission from a patient who may be an infection risk, Class N
  • Negative room air pressure with additional barriers including an Anteroom, also known as Class Q for quarantine isolation (COVID-19, Tuberculosis, etc.) .

How does a negative pressure room work

Negative pressure is generated and maintained by a ventilation system that removes more air from the room than is allowed to enter the room.  With a negative pressure room outside air flows into the room through a gap under the door (typically about one half-inch high). Except for this gap, the room is as airtight as possible.  All other cracks and gaps, such as those around windows, light fixtures and electrical outlets are sealed, since leakage through these gaps can compromise or eliminate room negative pressure.

Because generally there are components of the exhausted air such as chemical contaminants, microorganisms, or radioactive isotopes that must not be released to the surrounding outdoor environment (indeed, the original purpose of the negative-pressure room), any air outlet must, at a minimum, be located such that it will not expose people or other occupied spaces.  In a negative pressure room exhaust air is exhausted through the roof of the building. However, in some cases, such as when highly infections microorganisms are present, for example in a biosafety level 4 room, the air must first be mechanically filtered or disinfected by ultraviolet irradiation or chemical means before being released to the surrounding outdoor environment. In the case of nuclear facilities the air is monitored for the presence of radioactive isotopes and usually filtered before being exhausted through a tall exhaust duct to be released higher in the air away from occupied spaces.

To maintain a negative pressure in isolation rooms two areas must be considered;  the room itself and the corridor or hall directly outside the room.

  • For AIIR, the room should be negatively pressurized in relation to the corridor. This helps to prevent infectious particles from escaping the room envelope. If an anteroom is present between the AIIR and the corridor, the AIIR may be negatively or positively pressurized compared to the anteroom. However, if the AIIR is positively pressurized to the anteroom, the anteroom must be negatively pressurized to the corridor.
  • A difference in pressure always causes air to move from areas at higher pressure to those at lower pressure. The greater the pressure difference, the faster the air will move. This air movement helps provide containment of infectious particles by moving the air from a clean area to a less clean area.
  • The differential pressure or pressure offset between the two areas is established by mechanically adjusting the supply and exhaust air. For a negative pressure room, the sum of the mechanically exhausted air must exceed the sum of the mechanically supplied air. This offset forces air to enter the room under the door and through other leaks thus preventing infectious particles from escaping.
  • In order to maintain consistent offset airflow, the difference between exhaust and supply should create a pressure differential of at least 0.01 inch water gauge (wg) or 2.5 Pascals (Pa).  Pressure in this application is used to move the air from adjacent spaces into the isolation room.

Hospital negative pressure room

Creating positive and negative pressure rooms requires the use of specialized construction and climate control equipment. A minimum of 12 air-flow changes each hour (ACH) must be maintained.  In some situations even greater ACH may be required.  The following must also be addressed:

  • The recirculation of air through HEPA filters to control the movement of airborne contaminants;
  • Self-closing entryway with an adequate seal must be provided;
  • Thoroughly sealing floors, ceiling, walls, and windows;
  • Properly sized fans and ductwork must be specified to move air in the desired directions;
  • A monitoring system that allows users to adjust pressure when necessary;
  • Intermediate environment between the pressure room and outside environment for deliveries, observations, and protective gear storage must be provided.

Some medical facilities additionally incorporate UV radiation into the system to help maintain a sterile environment. Using UV light in a filtration system sterilizes particles and reduces viruses (such as coronavirus) in the quarantine space, helping to protect healthcare workers who enter the room to service the quarantined patient.

Once the area is in service, terminal cleaning should occur, after sufficient time has elapsed for enough air flow to remove potentially infectious particles. For information on determining air changes per hour (ACH), see this instructional video. The facility should determine the desired efficiency for removal based on the CDC table duplicated below. The original table and references in the note may be found at the following link: https://www.cdc.gov/infectioncontrol/guidelines/environmental/appendix/air.html#tableb1erminal


2 138 207
4 69 104
6+ 46 69
8 35 52
10+ 28 41
12+ 23 35
15+ 18 28
20 14 21
50 6 8

Patient Placement

The CDC recommends the following for patients positively identified as infected with COVID-19 virus:

  • Evaluate the need for hospitalization. If hospitalization is not medically necessary, home care is preferable if the individual’s situation allows.
  • If admitted to a hospital, place a patient with suspected or confirmed SARS-CoV-2 infection in a single-person room with the door closed. The patient should have a dedicated bathroom.
    • Airborne Infection Isolation Rooms (AIIRs) should be reserved for patients who will be undergoing aerosol generating procedures
  • Personnel entering the room should use PPE as described below.
  • As a measure to limit Health Care Partners (HCP) exposure and conserve personal protective equipment (PPE), facilities could consider designating entire units within the facility, with dedicated HCP, to care for patients with suspected or confirmed SARS-CoV-2 infection. Dedicated means that HCP are assigned to care only for these patients during their shift.
    • Determine how staffing needs will be met as the number of patients with suspected or confirmed SARS-CoV-2 infection increase and if HCP become ill and are excluded from work.
    • It might not be possible to distinguish patients who have COVID-19 from patients with other respiratory viruses. As such, patients with different respiratory pathogens might be cohorted on the same unit. However, only patients with the same respiratory pathogen may be housed in the same room. For example, a patient with COVID-19 should ideally not be housed in the same room as a patient with an undiagnosed respiratory infection or a respiratory infection caused by a different pathogen.
  • To the extent possible, patients with suspected or confirmed SARS-CoV-2 infection should be housed in the same room for the duration of their stay in the facility (e.g., minimize room transfers).
  • Limit transport and movement of the patient outside of the room to medically essential purposes.
    • Whenever possible, perform procedures/tests in the patient’s room.
    • Consider providing portable x-ray equipment in patient cohort areas to reduce the need for patient transport.
  • Communicate information about patients with suspected or confirmed SARS-CoV-2 infection to appropriate personnel before transferring them to other departments in the facility (e.g., radiology) and to other healthcare facilities.
  • Patients should wear a facemask or cloth face covering to contain secretions during transport. If patients cannot tolerate a facemask or cloth face covering or one is not available, they should use tissues to cover their mouth and nose while out of their room.
  • Once the patient has been discharged or transferred, HCP, including environmental services personnel, should refrain from entering the vacated room until sufficient time has elapsed for air changing equipment to remove potentially infectious particles (more information on clearance rates under differing ventilation conditions is available). Once this time has elapsed, the room should undergo appropriate cleaning and surface disinfection before it is returned to routine use.

In addition to these minimal recommendations, the CDC also advises the use of a dependable and accurate. monitoring system for maintaining secure AIIR standards.

CDC negative pressure room requirements

Airborne infection isolation (AII) refers to the isolation of patients infected with organisms spread via airborne droplet nuclei <5 µm in diameter. This isolation area receives numerous air changes per hour (ACH) (>12 ACH for new construction as of 2001; >6 ACH for construction before 2001), and is under negative pressure, such that the direction of the air flow is from the outside adjacent space (e.g., the corridor) into the room. The air in an AII room is preferably exhausted to the outside of a building, but may be recirculated provided that the return air is filtered through a high-efficiency particulate air (HEPA) filter. The use of personal respiratory protection is also indicated for persons entering these rooms when caring for TB or smallpox patients and for staff who lack immunity to airborne viral diseases (e.g., measles or varicella zoster virus [VZV] infection).

Protective environment (PE) is a specialized patient-care area, usually in a hospital, with a positive air flow relative to the corridor (i.e., air flows from the room to the outside adjacent space). The combination of HEPA filtration, high numbers of air changes per hour (>12 ACH), and minimal leakage of air into the room creates an environment that can safely accommodate patients who have undergone allogeneic hematopoietic stem cell transplant (HSCT).


I. Air-Handling Systems in Health-Care Facilities

Use AIA guidelines as minimum standards where state or local regulations are not in place for design and construction of ventilation systems in new or renovated health-care facilities. Ensure that existing structures continue to meet the specifications in effect at the time of construction (1). Category IC (AIA: 1.1.A, 5.4)
Monitor ventilation systems in accordance with engineers’ and manufacturers’ recommendations to ensure preventive engineering, optimal performance for removal of particulates, and elimination of excess moisture (1–8). Category IB, IC (AIA: 7.2, 7.31.D, 8.31.D, 9.31.D, 10.31.D, 11.31.D, Environmental Protection Agency [EPA] guidance)

1. Ensure that heating, ventilation, air conditioning (HVAC) filters are properly installed and maintained to prevent air leakages and dust overloads (2,4,6,9). Category IB
2. Monitor areas with special ventilation requirements (e.g., AII or PE) for ACH, filtration, and pressure differentials (1,7,8,10–26). Category IB, IC (AIA: 7.2.C7, 7.2.D6)

a. Develop and implement a maintenance schedule for ACH, pressure differentials, and filtration efficiencies by using facility-specific data as part of the multidisciplinary risk assessment. Take into account the age and reliability of the system.
b. Document these parameters, especially the pressure differentials.

3. Engineer humidity controls into the HVAC system and monitor the controls to ensure adequate moisture removal (1). Category IC (AIA: 7.31.D9)

a. Locate duct humidifiers upstream from the final filters.
b. Incorporate a water-removal mechanism into the system.
c. Locate all duct takeoffs sufficiently downstream from the humidifier so that moisture is completely absorbed.

4. Incorporate steam humidifiers, if possible, to reduce potential for microbial proliferation within the system, and avoid use of cool-mist humidifiers. Category II
5. Ensure that air intakes and exhaust outlets are located properly in construction of new facilities and renovation of existing facilities (1,27). Category IC (AIA: 7.31.D3, 8.31.D3, 9.31.D3, 10.31.D3, 11.31.D3)

a. Locate exhaust outlets &gt;25 ft from air-intake systems.
b. Locate outdoor air intakes &gt;6 ft above ground or &gt;3 ft above roof level.
c. Locate exhaust outlets from contaminated areas above roof level to minimize recirculation of exhausted air.

6. Maintain air intakes and inspect filters periodically to ensure proper operation (1,11–16,27). Category IC (AIA: 7.31.D8)
7. Bag dust-filled filters immediately upon removal to prevent dispersion of dust and fungal spores during transport within the facility (4,28). Category IB

a. Seal or close the bag containing the discarded filter.
b. Discard spent filters as regular solid waste, regardless of the area from which they were removed (28).

8. Remove bird roosts and nests near air intakes to prevent mites and fungal spores from entering the ventilation system (27,29,30). Category IB
9. Prevent dust accumulation by cleaning air-duct grilles in accordance with facility-specific procedures and schedules and when rooms are not occupied by patients (1,10–16). Category IC, II (AIA: 7.31.D10)
10. Periodically measure output to monitor system function; clean ventilation ducts as part of routine HVAC maintenance to ensure optimum performance (1,31,32). Category IC, II (AIA: 7.31.D10)

Use portable, industrial-grade HEPA filter units capable of filtration rates in the range of 300–800 ft3/min to augment removal of respirable particles as needed (33). Category II

1. Select portable HEPA filters that can recirculate all or nearly all of the room air and provide the equivalent of &gt;12 ACH (34). Category II
2. Portable HEPA filter units placed in construction zones can be used later in patient-care areas, provided all internal and external surfaces are cleaned, and the filter replaced or its
performance verified by appropriate particle testing. Category II
3. Situate portable HEPA units with the advice of facility engineers to ensure that all room air is filtered (34). Category II
4. Ensure that fresh-air requirements for the area are met (33,35). Category II

Follow appropriate procedures for use of areas with through-the-wall ventilation units (1). Category IC (AIA: 8.31.D1, 8.31.D8, 9.31.D23, 10.31.D18, 11.31.D15)

1. Do not use such areas as PE rooms (1). Category IC (AIA: 7.2.D3)
2. Do not use a room with a through-the-wall ventilation unit as an AII room unless it can be demonstrated that all required AII engineering controls are met (1,34). Category IC (AIA:7.2.C3)

Conduct an infection-control risk assessment (ICRA) and provide an adequate number of AII and PE rooms (if required) or other areas to meet the needs of the patient population (1,2,7,8,17,19, 20,34,36–43). Category IA, IC (AIA: 7.2.C, 7.2.D)
When ultraviolet germicidal irradiation (UVGI) is used as a supplemental engineering control, install fixtures 1) on the wall near the ceiling or suspended from the ceiling as an upper air unit; 2) in the air-return duct of an AII area; or 3) in designated enclosed areas or booths for sputum induction (34). Category II
Seal windows in buildings with centralized HVAC systems, including PE areas (1,3,44). Category IB, IC (AIA: 7.2.D3)
Keep emergency doors and exits from PE rooms closed except during an emergency; equip emergency doors and exits with alarms. Category II
Develop a contingency plan for backup capacity in the event of a general power failure (45). Category IC (Joint Commission on Accreditation of Healthcare Organizations [JCAHO]: Environment of Care [EC] 1.4)

1. Emphasize restoration of appropriate air quality and ventilation conditions in AII rooms, PE rooms, operating rooms, emergency departments, and intensive care units (1,45). Category IC (AIA: 1.5.A1; JCAHO: EC 1.4)
2. Deploy infection-control procedures to protect occupants until power and systems functions are restored (1,36,45). Category IC (AIA: 5.1, 5.2; JCAHO: EC 1.4)

Do not shut down HVAC systems in patient-care areas except for maintenance, repair, testing of emergency backup capacity, or new construction (1,46). Category IB, IC (AIA: 5.1, 5.2.B, C)

1. Coordinate HVAC system maintenance with infection-control staff and relocate immunocompromised patients if necessary (1). Category IC (AIA: 5.1, 5.2)
2. Provide backup emergency power and air-handling and pressurization systems to maintain filtration, constant ACH, and pressure differentials in PE rooms, AII rooms, operating rooms, and other critical-care areas (1,37,47). Category IC (AIA: 5.1, 5.2)
3. For areas not served by installed emergency ventilation and backup systems, use portable units and monitor ventilation parameters and patients in those areas (33). Category II
4. Coordinate system startups with infection-control staff to protect patients in PE rooms from bursts of fungal spores (1,3,37,47). Category IC (AIA: 5.1, 5.2)
5. Allow sufficient time for ACH to clean the air once the system is operational (Table 1) (1,33). Category IC (AIA: 5.1, 5.2)

HVAC systems serving offices and administrative areas may be shut down for energy conservation purposes, but the shutdown must not alter or adversely affect pressure differentials maintained in laboratories or critical-care areas with specific ventilation requirements (i.e., PE rooms, AII rooms, operating rooms).

Category II
Whenever possible, avoid inactivating or shutting down the entire HVAC system, especially in acute-care facilities.

Category II
Whenever feasible, design and install fixed backup ventilation systems for new or renovated construction of PE rooms, AII rooms, operating rooms, and other critical-care areas identified by ICRA (1). Category IC (AIA: 1.5.A1)
II. Construction, Renovation, Remediation, Repair, and Demolition

Establish a multidisciplinary team that includes infection-control staff to coordinate demolition, construction, and renovation projects and consider proactive preventive measures at the inception; produce and maintain summary statements of the team’s activities (1,9,11–16,38,48–51). Category IB, IC (AIA: 5.1)
Educate both the construction team and health-care staff in immunocompromised patient-care areas regarding the airborne infection risks associated with construction projects, dispersal of fungal spores during such activities, and methods to control the dissemination of fungal spores (11–16,27,50,52–56).

Category IB
Incorporate mandatory adherence agreements for infection control into construction contracts, with penalties for noncompliance and mechanisms to ensure timely correction of problems (1,11,13–16,27,50). Category IC (AIA: 5.1)
Establish and maintain surveillance for airborne environmental disease (e.g., aspergillosis) as appropriate during construction, renovation, repair, and demolition activities to ensure the health and safety of immunocompromised patients (27,57–59). Category IB

1. Using active surveillance, monitor for airborne infections in immunocompromised patients (27,37,57,58). Category IB
2. Periodically review the facility’s microbiologic, histopathologic, and postmortem data to identify additional cases (27,37,57,58). Category IB
3. If cases of aspergillosis or other health-care–associated airborne fungal infections occur, aggressively pursue the diagnosis with tissue biopsies and cultures as feasible (11,13–16,27,50,57–59). Category IB

Implement infection-control measures relevant to construction, renovation, maintenance, demolition, and repair (1,16,49,50,60). Category IB, IC (AIA: 5.1, 5.2)

1. Before the project gets under way, perform an ICRA to define the scope of the activity and the need for barrier measures (1,11,13–16,48–51,60). Category IB, IC (AIA: 5.1)

a. Determine if immunocompromised patients may be at risk for exposure to fungal spores from dust generated during the project (13–16,48,51).
b. Develop a contingency plan to prevent such exposures (13–16,48,51).

2. Implement infection-control measures for external demolition and construction activities (11,13–16,50,61,62). Category IB

a. Determine if the facility can operate temporarily on recirculated air; if feasible, seal off adjacent air intakes.
b. If this is not possible or practical, check the low-efficiency (roughing) filter banks frequently and replace as needed to avoid buildup of particulates.
c. Seal windows and reduce wherever possible other sources of outside air intrusion (e.g., open doors in stairwells and corridors), especially in PE areas.

3. Avoid damaging the underground water system (i.e., buried pipes) to prevent soil and dust contamination of the water (1,63). Category IB, IC (AIA: 5.1)
4. Implement infection-control measures for internal construction activities (1,11,13–16,48– 50,64). Category IB, IC (AIA: 5.1, 5.2)

a. Construct barriers to prevent dust from construction areas from entering patient-care areas; ensure that barriers are impermeable to fungal spores and in compliance with local fire codes (1,45,48,49,55,64–66).
b. Seal off and block return air vents if rigid barriers are used for containment (1,16,50).
c. Implement dust-control measures on surfaces and divert pedestrian traffic away from work zones (1,48,49,64).
d. Relocate patients whose rooms are adjacent to work zones, depending on their immune status, the scope of the project, the potential for generation of dust or water aerosols, and the methods used to control these aerosols (1,64,65).

5. Perform those engineering and work-site related infection-control measures as needed for internal construction, repairs, and renovations (1,48,49,51,64,66). Category IB, IC (AIA:5.1, 5.2)

a. Ensure proper operation of the air-handling system in the affected area after erection of barriers and before the room or area is set to negative pressure (39,47,50,64). Category IB

b. Create and maintain negative air pressure in work zones adjacent to patient-care areas and ensure that required engineering controls are maintained (1,48,49,51,64,66).
c. Monitor negative airflow inside rigid barriers (1,67).
d. Monitor barriers and ensure integrity of the construction barriers; repair gaps or breaks in barrier joints (1,65,66,68).
e. Seal windows in work zones if practical; use window chutes for disposal of large pieces of debris as needed, but ensure that the negative pressure differential for the area is maintained (1,13,48).
f. Direct pedestrian traffic from construction zones away from patient-care areas to minimize dispersion of dust (1,13–16,44,48–51,64).
g. Provide construction crews with 1) designated entrances, corridors, and elevators wherever practical; 2) essential services (e.g., toilet facilities) and convenience services (e.g., vending machines); 3) protective clothing (e.g., coveralls, footgear, and headgear) for travel to patient-care areas; and 4) a space or anteroom for changing clothing and storing equipment (1,11,13–16,50).
h. Clean work zones and their entrances daily by 1) wet-wiping tools and tool carts before their removal from the work zone; 2) placing mats with tacky surfaces inside the entrance; and 3) covering debris and securing this covering before removing debris from the work zone (1,11,13–16,50).
i. In patient-care areas, for major repairs that include removal of ceiling tiles and disruption of the space above the false ceiling, use plastic sheets or prefabricated plastic units to contain dust; use a negative pressure system within this enclosure to remove dust; and either pass air through an industrial-grade, portable HEPA filter capable of filtration rates of 300–800 ft3/min., or exhaust air directly to the outside (16,50,64,67,69).
j. Upon completion of the project, clean the work zone according to facility procedures, and install barrier curtains to contain dust and debris before removing rigid barriers (1,11,13–16,48–50).
k. Flush the water system to clear sediment from pipes to minimize waterborne microorganism proliferation (1,63).
l. Restore appropriate ACH, humidity, and pressure differential; clean or replace air filters; dispose of spent filters (3,4,28,47).

Use airborne-particle sampling as a tool to evaluate barrier integrity (3,70). Category II
Commission the HVAC system for newly constructed health-care facilities and renovated spaces before occupancy and use, with emphasis on ensuring proper ventilation for operating rooms, AII rooms, and PE areas (1,70–72). Category IC (AIA: 5.1; ASHRAE: 1-1996)
No recommendation is offered regarding routine microbiologic air sampling before, during, or after construction, or before or during occupancy of areas housing immunocompromised patients (9,48,49,51,64,73,74).

Unresolved issue
If a case of health-care–acquired aspergillosis or other opportunistic environmental airborne fungal disease occurs during or immediately after construction, implement appropriate follow-up measures (40,48,75–78). Category IB

1. Review pressure-differential monitoring documentation to verify that pressure differentials in the construction zone and in PE rooms are appropriate for their settings (1,40,78). Category IB, IC (AIA: 5.1)
2. Implement corrective engineering measures to restore proper pressure differentials as needed (1,40,78). Category IB, IC (AIA: 5.1)
3. Conduct a prospective search for additional cases and intensify retrospective epidemiologic review of the hospital’s medical and laboratory records (27,48,76,79,80). Category IB
4. If no epidemiologic evidence of ongoing transmission exists, continue routine maintenance in the area to prevent health-care–acquired fungal disease (27,75). Category IB

If no epidemiologic evidence exists of ongoing transmission of fungal disease, conduct an environmental assessment to find and eliminate the source (11,13–16,27,44,49–51,60,81). Category IB

1. Collect environmental samples from potential sources of airborne fungal spores, preferably by using a high-volume air sampler rather than settle plates (2,4,11,13–16,27,44,49,50,64,65,81–86). Category IB
2. If either an environmental source of airborne fungi or an engineering problem with filtration or pressure differentials is identified, promptly perform corrective measures to eliminate the source and route of entry (49,60). Category IB
3. Use an EPA-registered antifungal biocide (e.g., copper-8-quinolinolate) for decontaminating structural materials (16,61,66,87). Category IB
4. If an environmental source of airborne fungi is not identified, review infection-control measures, including engineering controls, to identify potential areas for correction or improvement (88,89). Category IB
5. If possible, perform molecular subtyping of Aspergillus spp. isolated from patients and the environment to compare their strain identities (90–94). Category II

If air-supply systems to high-risk areas (e.g., PE rooms) are not optimal, use portable, industrial-grade HEPA filters on a temporary basis until rooms with optimal air-handling systems become available (1,13–16,27,50). Category II

III. Infection Control and Ventilation Requirements for PE rooms

Minimize exposures of severely immunocompromised patients (e.g., solid-organ transplant patients or allogeneic neutropenic patients) to activities that might cause aerosolization of fungal spores (e.g., vacuuming or disruption of ceiling tiles) (37,48,51,73). Category IB
Minimize the length of time that immunocompromised patients in PE are outside their rooms for diagnostic procedures and other activities (37,62). Category IB
Provide respiratory protection for severely immunocompromised patients when they must leave PE for diagnostic procedures and other activities; consult the most recent revision of CDC’s Guideline for Prevention of Health-Care–Associated Pneumonia for information regarding the appropriate type of respiratory protection. (27,37). Category II
Incorporate ventilation engineering specifications and dust-controlling processes into the planning and construction of new PE units (Figure 1). Category IB, IC

1. Install central or point-of-use HEPA filters for supply (incoming) air (1,2,27,48,56,70, 80,82,85,95–102). Category IB, IC (AIA: 5.1, 5.2, 7.2.D)
2. Ensure that rooms are well-sealed by 1) properly constructing windows, doors, and intake and exhaust ports; 2) maintaining ceilings that are smooth and free of fissures, open joints, and crevices; 3) sealing walls above and below the ceiling; and 4) monitoring for leakage and making any necessary repairs (1,27,44,100,101). Category IB, IC (AIA: 7.2.D3)
3. Ventilate the room to maintain &gt;12 ACH (1,27,37,100,101,103). Category IC (AIA: 7.2.D)
4. Locate air supply and exhaust grilles so that clean, filtered air enters from one side of the room, flows across the patient’s bed, and exits from the opposite side of the room (1,27,100,101). Category IC (AIA: 7.31.D1)
5. Maintain positive room air pressure (&gt;2.5 Pa [0.01-inch water gauge]) in relation to the corridor (1,3,27,100,101). Category IB, IC (AIA: Table 7.2)
6. Maintain airflow patterns and monitor these on a daily basis by using permanently installed visual means of detecting airflow in new or renovated construction, or by using other visual methods (e.g., flutter strips or smoke tubes) in existing PE units. Document the monitoring results (1,13). Category IC (AIA: 7.2.D6)
7. Install self-closing devices on all room exit doors in PE rooms (1). Category IC (AIA: 7.2.D4)

Do not use laminar air flow systems in newly constructed PE rooms (99,101). Category II
Take measures to protect immunocompromised patients who would benefit from a PE room and who also have an airborne infectious disease (e.g., acute VZV infection or tuberculosis).

1. Ensure that the patient’s room is designed to maintain positive pressure.
2. Use an anteroom to ensure appropriate air-balance relationships and provide independent exhaust of contaminated air to the outside, or place a HEPA filter in the exhaust duct if the return air must be recirculated (1,100) (Figure 2). Category IC (AIA: 7.2.D1, A7.2.D)
3. If an anteroom is not available, place the patient in AII and use portable, industrial-grade HEPA filters to enhance filtration of spores in the room (33). Category II

Maintain backup ventilation equipment (e.g., portable units for fans or filters) for emergency provision of required ventilation for PE areas and take immediate steps to restore the fixed ventilation system (1,37,47). Category IC (AIA: 5.1)

IV. Infection-Control and Ventilation Requirements for AII Rooms

Incorporate certain specifications into the planning and construction or renovation of AII units (1,34,100,101,104) (Figure 3). Category IB, IC

1. Maintain continuous negative air pressure (2.5 Pa [0.01 inch water gauge]) in relation to the air pressure in the corridor; monitor air pressure periodically, preferably daily, with audible manometers or smoke tubes at the door (for existing AII rooms), or with a permanently installed visual monitoring mechanism. Document the results of monitoring (1,100,101). Category IC (AIA: 7.2.C7, Table 7.2)
2. Ensure that rooms are well-sealed by properly constructing windows, doors, and air-intake and exhaust ports; when monitoring indicates air leakage, locate the leak and make necessary repairs (1,99,100). Category IB, IC (AIA: 7.2.C3)
3. Install self-closing devices on all AII room exit doors (1). Category IC (AIA: 7.2.C4)
4. Provide ventilation to ensure &gt;12 ACH for renovated rooms and new rooms, and &gt;6 ACH for existing AII rooms (1,34,104). Category IB, IC (AIA: Table 7.2)
5. Direct exhaust air to the outside, away from air-intake and populated areas. If this is not practical, air from the room can be recirculated after passing through a HEPA filter (1,34). Category IC (AIA: Table 7.2)

Where supplemental engineering controls for air cleaning are indicated from a risk assessment of the AII area, install UVGI units in the exhaust air ducts of the HVAC system to supplement HEPA filtration or install UVGI fixtures on or near the ceiling to irradiate upper room air (34). Category II
Implement environmental infection-control measures for persons with diagnosed or suspected airborne infectious diseases.

1. Use AII rooms for patients with or suspected of having an airborne infection who also require cough-inducing procedures, or use an enclosed booth that is engineered to provide 1) &gt;12 ACH; 2) air supply and exhaust rate sufficient to maintain a 2.5 Pa (0.01-inch water gauge) negative pressure difference with respect to all surrounding spaces with an exhaust
rate of &gt;50 ft3/min; and 3) air exhausted directly outside away from air intakes and traffic or exhausted after HEPA filtration before recirculation (1,34,105–107). Category IB, IC (AIA: 7.15.E, 7.31.D23, 9.10, Table 7.2)
2. Although airborne spread of viral hemorrhagic fever (VHF) has not been documented in a health-care setting, prudence dictates placing a VHF patient in an AII room, preferably with an anteroom, to reduce the risk of occupational exposure to aerosolized infectious material in blood, vomitus, liquid stool, and respiratory secretions present in large amounts during the end stage of a patient’s illness (108–110). Category II

a. If an anteroom is not available, use portable, industrial-grade HEPA filters in the patient’s room to provide additional ACH equivalents for removing airborne particulates.
b. Ensure that health-care workers wear face shields or goggles with appropriate respirators when entering the rooms of VHF patients with prominent cough, vomiting, diarrhea, or hemorrhage (109).

3. Place smallpox patients in negative pressure rooms at the onset of their illness, preferably using a room with an anteroom, if available (36). Category II

No recommendation is offered regarding negative pressure or isolation for patients with Pneumocystis carinii pneumonia (111–113). Unresolved issue.
Maintain backup ventilation equipment (e.g., portable units for fans or filters) for emergency provision of ventilation requirements for AII rooms, and take immediate steps to restore the fixed ventilation system (1,34,47). Category IC (AIA: 5.1)

V. Infection-Control and Ventilation Requirements for Operating Rooms

Implement environmental infection-control and ventilation measures for operating rooms.

1. Maintain positive-pressure ventilation with respect to corridors and adjacent areas (1,114,115). Category IB, IC (AIA: Table 7.2)
2. Maintain &gt;15 ACH, of which &gt;3 ACH should be fresh air (1,116,117). Category IC (AIA: Table 7.2)
3. Filter all recirculated and fresh air through the appropriate filters, providing 90% efficiency (dust-spot testing) at a minimum (1,118). Category IC (AIA: Table 7.3)
4. In rooms not engineered for horizontal laminar airflow, introduce air at the ceiling and exhaust air near the floor (1,115,119). Category IC (AIA: 7.31.D4)
5. Do not use ultraviolet (UV) lights to prevent surgical-site infections (115,120–126). Category IB
6. Keep operating room doors closed except for the passage of equipment, personnel, and patients, and limit entry to essential personnel (127,128). Category IB

Follow precautionary procedures for infectious TB patients who also require emergency surgery (34,129,130). Category IB, IC

1. Use an N95 respirator approved by the National Institute for Occupational Safety and Health without exhalation valves in the operating room (129,131). Category IC (Occupational Safety and Health Administration [OSHA]; 29 Code of Federal Regulations [CFR] 1910.134,139)
2. Intubate the patient in either the AII room or the operating room; if intubating the patient in the operating room, do not allow the doors to open until 99% of the airborne contaminants are removed (Table 1) (34,117). Category IB
3. When anesthetizing a patient with confirmed or suspected TB, place a bacterial filter between the anesthesia circuit and patient’s airway to prevent contamination of anesthesia equipment or discharge of tubercle bacilli into the ambient air (130,132). Category IB
4. Extubate and allow the patient to recover in an AII room (34,117). Category IB
5. If the patient has to be extubated in the operating room, allow adequate time for ACH to clean 99% of airborne particles from the air (Table 1), because extubation is a cough-producing procedure (34,117). Category IB

Use portable, industrial-grade HEPA filters temporarily for supplemental air cleaning during intubation and extubation for TB patients who require surgery (33,34,117). Category II

1. Position the units appropriately so that all room air passes through the filter; obtain engineering consultation to determine the appropriate placements (34). Category II
2. Switch the portable unit off during the surgical procedure. Category II
3. Provide fresh air as per ventilation standards for operating rooms; portable units do not meet the requirements for the number of fresh ACH (1,33,133). Category II

If possible, schedule TB patients as the last surgical cases of the day to maximize the time available for removal of airborne contamination. Category II
No recommendation is offered for performing orthopedic implant operations in rooms supplied with laminar airflow (118,120). Unresolved issue
Maintain backup ventilation equipment (e.g., portable units for fans or filters) for emergency ventilation of operating rooms, and take immediate steps to restore the fixed ventilation system (1,47,131,134). Category IB, IC (AIA: 5.1)

VI. Other Potential Infectious Aerosol Hazards in Health-Care Facilities

In settings where surgical lasers are used, wear appropriate personal protective equipment (PPE), including N95 or N100 respirators, to minimize exposure to laser plumes (129,135,136). Category IC (OSHA; 29 CFR 1910.134,139)
Use central wall suction units with in-line filters to evacuate minimal laser plumes (135–138). Category II
Use a mechanical smoke evacuation system with a high-efficiency filter to manage the generation of large amounts of laser plume, when ablating tissue infected with human papilloma virus (HPV) or performing procedures on a patient with extrapulmonary TB (34,136,137,139–141). Category II


Negative room pressure monitor

Installing a Permanent Room Pressure Monitor

After a new AIIR is constructed and before it is occupied, the mechanical contractor will adjust the airflow quantities as directed by the engineer to ensure that it operates as designed. However, mechanical systems do drift out of balance over time. It is important to regularly check that an AIIR is still operating under negative pressure; planning for this should be included in the initial mechanical design of the room.

Room pressure monitors should be used as a supplement to daily visual checks when the room is in use. The most reliable way to monitor negative pressure is to install a permanent electronic room pressure monitor as part of the construction project. When properly selected and installed, a room pressure monitor can provide continuous qualitative and quantitative confirmation of negative pressure across a room boundary.

There are two common types of permanent pressure monitors: those that measure and display the actual air pressure difference between the AIIR and the reference space; and those that measure and display the actual air pressure difference between the AIIR and the reference space as well as chart, log and record all monitored variables.

Either type is suitable for an AIIR, but monitors which record and log values provide a pressure history so that if an unacceptable pressure reading occurred when no person was present the deviation will be known. Pressure differentials across room boundaries can be very small, often in the range of thousandths of an inch. For example, the CDC Guidelines recommend that negative pressure be at least ≥ 0.01″ of water gauge. Some devices that measure differential pressure are not accurate to this level. Before specifying or purchasing a room pressure monitor, make sure that the device is capable of accurately and reliably measuring a pressure difference this small.

Alarm(s) and Controls

In addition to providing a continuous readout of the pressure difference, the wall panel should include an audible and visual alarm to warn staff when pressurization is lost. The alarm will sound when the measured room pressurization drifts to less than the monitor’s reference pressure value. Reference pressure valves are programmed into the unit by an engineer or trained staff member. It will be a value between the steady state pressure differential maintained by the room and zero (neutral pressure). For example, in a room with a steady state pressure differential of minus 0.03″ W.G., the alarm could be programmed to activate when the pressure differential rises to minus 0.001″ W.G.. Minus 0.001″ W.G. is the reference pressure value. The wall panel should also allow staff to program a built-in time delay between loss of pressurization and alarm activation. The time delay will allow staff a sufficient interval to routinely enter and leave the room without setting off the alarm.

A typical time delay is 30 to 45 seconds. The audible alarm is usually a beeping sound, which will stop when negative pressure is restored or when a “mute” button on the panel is pressed. The visual alarm usually consists of a red warning light and/or a flashing message on the LCD. Most wall panels also have a green “normal” or “safe” light, which indicates that the monitor is operating and negative pressure is within programmed parameters.

Remote Alarm

In addition to the alarm included on the wall panel, most room pressure monitors include an extra identical signal that allows a “safe” or “alarm” signal to be sent from the wall panel to a remote location. Common locations for this remote alarm are the nurses’ station, the engineering department, and the central switchboard. It is usually possible to connect the alarm signals from a number of AIIR monitors to a remote alarm panel. In California, for example, the hospital building codes require that AIIRs be equipped with an alarm that annunciates at the room and at a nurses’ station or other suitable location. Ideally, the room pressure monitor would integrate with the facility building management system; i.e. BACnet.

Other Optional Features

There are a number of room pressure monitors available with additional options. Examples of such options include: the ability to receive text alerts, email alerts and automated phone calls if room pressure readings/values fall outside desired operating ranges. Other options might be the ability to generate log reports, and plot values over a specified period of time.


Negative pressure isolation rooms, AIIR rooms, and critically controlled environments are becoming more and more common – and more important. Maintaining room pressure (negative or positive) is critical for controlled applications where human health and wellness are considered. Just as important as controlling critical environments is monitoring these spaces to ensure they maintain proper pressure differentials, air changes, and warning systems.


Stop COVID-19 From Spreading – Isolation Room Safety

Isolation Room Basics

Isolation rooms are controlled, critical environments in hospitals. When patients have communicable diseases like COVID-19, they are normally placed in one of these isolation rooms. Isolation rooms achieve their effectiveness in controlling contagious disease by keeping internal room pressures lower that areas outside of the room, thus keeping all of the ‘bad stuff’ inside the room. It is easy to determine that a room is a negative pressure room by opening the door.  If the door of negative pressure room is opened a rush of air enters the room. This happens because areas of higher pressure (i.e. areas outside of the isolation room) will naturally move to areas of lower pressure (i.e. the isolation room interior).

The function if the room is simple; if air rushes in, when a doctor or nurse enters to treat the affected patient, theoretically no infected air from within the patient room can escape through an open door.

More protection needed

Most hospitals already have some isolation rooms. Recently, however, hospitals have become overwhelmed with cases of COVID-19 (Coronavirus), and they are in need of additional isolation rooms.  This has led to creating temporary isolation rooms to maintain the safety by protecting caregivers, patients, doctors, nurses, and the general public.  Although creating these negative pressure rooms is simple in theory it is sometimes difficult to achieve.

A critical aspect of maintaining correct pressures of an isolation room is the ability to monitor the actual negative pressure differential.  It is not enough to determine whether a room is a negative pressure room by opening the door and feeling the air from the hall flow into the room.  It is crucial to use some form of instrumentation. In years past, many hospitals turned to a device known as a “Ball In The Wall” or a “Ball In Tube” pressure indicator. These simple devices can be easily understood and implemented. They consist of a ball inside of a tube. Theoretically, when there is higher or lower pressure on a side of the tube protruding a wall, the ball “moves” from a direction of lower pressure to higher pressure, providing a visual indication of the pressure.

These work okay for general applications but fall very short when trying to control serious pandemic-scale diseases like COVID-19.

Here are some of the major downfalls of using “Ball In The Wall” pressure indicators for monitoring room pressure in isolation rooms.

  1. There is no way to determine the actual room pressure. Negative-pressure isolation rooms are required to maintain a minimum of  0.01-inch WC negative-pressure differential1 to the adjacent corridor whether or not an anteroom is utilized to keep communicable disease like COVID-19, SARS, H1N1, etc. under control. A simple Ball In Tube cannot display the actual differential air pressure. It can only indicate that there is some pressure differential present.
  2. No advanced alert system. Unlike more sophisticated systems and instruments, a simple ball in the wall can’t warn critical caregivers in advance if pressure in the isolation room is changing, indicate how much it has changed, or when it changed. Additionally, unlike more complete systems, the ball in the wall can’t notify staff by email, SMS, local alarm or other methods if the required pressure is not maintained.
  3. Another shortfall is the inability for a ball in a tube to report historic data conditions; i.e. when the room started gaining pressure, how long and at what tie the pressure was dangerous, etc… It does not log any pressures.

While these may sound optional, they are critically important attributes that any isolation room should have. Ultimately, it is what will help to stop the spread of COVID-19.

Why are Hospitals Still Using Ball In Wall Pressure Indicators?

Interestingly enough, some of the most technologically advanced hospitals are using these antiquated ball in tube systems to monitor pressure in isolation rooms, surgical rooms, and other critical environments.

One theory for their continued use is the simple fact that because everyone else is using it, it does not matter if it is effective, safe, or even functional. As long as it is widely accepted, then no one can be blamed if something goes wrong. Another theory, is that many “isolation rooms” are not actually maintaining negative pressure at the levels specified by overseeing compliance organizations.  This could be a case of “if I don’t know about it, I am not responsible for it.”

It could be said that many hospitals would have to spend a great deal of money to repair faulty equipment and modernize isolation rooms if they were to become aware of the true air pressure in these hospital rooms. When using ball in the wall type pressure indicators, there is a “yes/no” passing grade. Either the ball is visible or it isn’t. The margin for error is huge. The ball may indicate there is in fact some level of negative or positive pressure, but how much? It is near the threshold of leaving the room vulnerable and completely exposed to the public? It could be. Unfortunately, with the ball in the wall – there is no way to know for sure.

Unlike the ball in the wall indicators there are now modern pressure instruments that are calibrated with NIST traceability. This begs the question, “Just how accurate can mass produced ping-pong balls inside a plastic tube be?” Would you trust your patient’s lives or the health and safety of the public on a ball in a tube?

In short, it is a matter of public safety. In many hospitals, a ball in a tube is the only safeguard between a patient infected with a communicable disease like COVID-19 and the health and welfare of the public.

Better solutions

What are hospitals to do? Fortunately, there are many other instruments available which account for all of the holes and gaps in protection the ball in the wall fails to offer. In fact, many of these instruments cost much less and offer considerably more. In a logical world, the answer would be simple, get rid of the outdated and antiquated ball in the wall, and upgrade.

However, deeply ingrained processes and practices must be overcome. Fear of change and technological advance may paralyze the decision making process, even if it is for the betterment of the patient and the public as a whole.

We at Two Dimensional Instruments, LLC are providing hospitals with special pricing and support for our isolation room monitoring instruments through the deadly the COVID-19 outbreak. To learn more about what we can do for your hospital, please contact us or call 877-241-0042


1 Planning and maintaining hospital air isolation rooms
Controlling the spread of infectious diseases is essential to maintaining a safe care environment

Expectations of USP <797> vs cGMPs

ISO requirements for Compounding Sterile Pharmacies (CSP’s)

Expectations of USP <797>

Compounding Personnel

USP <797> F identifies that compounding personnel represent the greatest threat to the safety and efficacy of a CSP, and as such, these personnel must be fully trained prior to preparing any type of CSP. Training should include live/electronic instructional sources (where possible), professional and up-to-date publications in aseptic principles, and demonstration of aseptic skills. Personnel must pass practical and written evaluations (eg, gowning procedures, fingertip testing, air and surface monitoring) and participate in successful semiannual media fills.

Individuals who do not achieve these criteria must be immediately re-instructed and re-evaluated by expert compounding personnel to ensure all deficiencies are corrected. Media fill challenge testing, in which sterile fluid bacterial culture media is transferred via a sterile syringe and needle into a sterile container, is the most practical way to evaluate an individual’s skills in aseptic preparation. F

Air Monitoring

USP <797> states that procedural guidance and practice begins with well-designed and well-constructed facilities, wherein the preparation area (usually ISO 5) F is surrounded by areas of lower classifications, in this case ISO 7, 8, thereby creating a unidirectional airflow from the ISO 5 area (positive pressure) through the ISO 7 area (lower positive pressure area) to the ISO 8 (still lower positive pressure) area to an unclassified area (zero positive pressure, e.g. corridor). A robust sterile operations program must include non-viable, viable, and pressure differential monitoring F. Non-viable monitoring is conducted with particle monitoring devices (a non-continuous monitoring device) and ensures the minimization of particulate contamination. These devices are also referred to as “particle counters.”

Viable particle monitoring should be conducted with active air sampling devices (continuous monitoring device). An environmental sampling planF must be based on a risk assessment of the compounding activities performed. Selected sampling sites must include locations within each ISO Class 5, 7, and 8 area, and the plan should detail the sample locations, methods of collection, sampling frequencies, volume of air sampled, and time of day related to activity in the compounding area. The data must be reviewed and any upward trends investigated to ensure there are no adverse changes within the environment. Additionally, isolation of pathogenic or objectionable microorganisms must be investigated.

(Pic of typical cleanroom layout)

Differential Pressure

Differential pressure monitoring ensures the unidirectional flow of air from high pressure (ISO 5) to lower pressure (ISO 7 and 8) areas. Pressure gauges or velocity meters must be installed and the data reviewed and documented in a log every work shift (or at a minimum, daily). Alternatively, a continuous recording device (i.e. digital data logger and chart recorder – TV2 Cleanroom Monitor) can be used). The pressure difference between the ISO Class 7 and the general pharmacy area must be at least 5 Pascals (Pa) (0.02 inch water column). In facilities where low– and medium-risk level CSPs are prepared, the differential airflow must be maintained at a minimum velocity of 0.2 meters per second (40 feet per minute) between the buffer and ante areas.

Taking into consideration human error and standard risk calculations F, the best solution is using automated chart recorders, and data loggers, to ensure USP requirements for monitoring differential air pressure.

Expectations of USP <797>vs cGMPs


To minimize the potential of microbiological contamination, clean, disinfected surfaces are mandatory and a written cleaning and monitoring programF is required. The current industry standard practice is to use three disinfectants:

  1. Sterile isopropyl alcohol for disinfection of surfaces, instruments, and gloves
  2. A quaternary ammonium or phenolic product for daily and weekly disinfection
  3. A sporicidal agent (eg, accelerated hydrogen peroxide) for monthly disinfection or when microbiological spores are isolated

Surface monitoring will verify the surfaces are within established microbiological limits. A major difference between USP <797> and Current Good Manufacturing Practice regulations enforced by the FDA (cGMPs)F is that the latter requires disinfection qualification studies to demonstrate that disinfectants are efficacious against standard American Type Tissue Collection (ATTC) microorganisms and in-house isolates. Although these studies are expensive, time consuming, laborious, and not required by <797>, FDA may ultimately require they be conducted by a hospital pharmacy.

Both USP <797> and cGMPs require that surface sampling be performed in all ISO classified areas on a periodic basis using contact plates or swabs; <797> requires it be done at the conclusion of compounding. Sample locations must be defined in the EM planF or on a form and should include surface wipe sampling of the working areas in biological safety cabinets (BSCs); compounding aseptic containment isolators (CACIs); counter tops where finished preparations are placed; areas adjacent to BSCs and CACIs, including the floor directly under the work area; and patient administration areas. An investigation must be conducted when trends or pathogens/objectionable microorganisms are found.

Regulatory Divergence Between USP <797> and cGMPsF: The requirements of cGMPs are general and provide an overview of what is necessary for manufacturing facilities to produce safe and efficacious products. Interestingly, <797> sometimes provides more details than cGMPs.

HEPA Filter Leak Test

HEPA filtration, for example, is not mentioned in cGMPs and the only reference to air filtration is in it’s section § 211.46 Ventilation, air filtration, air heating and cooling: (c) Air filtration systems, including prefilters and particulate matter air filters, shall be used when appropriate on air supplies to production areas. If air is recirculated to production areas measures shall be taken to control recirculation of dust from production. In areas where air contamination occurs during production, there shall be adequate exhaust systems or other systems adequate to control contaminants. In contrast, <797> states: All HEPA filters shall be efficiency tested using the most penetrating particle size and shall be leak tested at the factory and then leak tested again in situ after installation.

However, FDA fills this and other cGMP voids by publishing Industry Guidance reportsF. For example, the Aseptic Processing guidance includes a section on HEPA filtration that recommends performing leak testing for each HEPA filter twice a year; USP <797> does not provide a definitive frequency for conducting leak testing. In this instance, FDA may expect a hospital pharmacy to follow cGMPs (the Aseptic Processing guidance) and conduct leak testing twice a year. Considering that HEPA filters produce unidirectional air that contacts surfaces and components used to prepare CSPs, this expectation is not unrealistic and should be adopted by pharmacy to ensure CSPs are not subject to extraneous airborne contaminants.

Pressure Differentials

A similar situation exists with differential pressures. USP <797> includes a section entitled, Pressure Differential Monitoring F that states, A pressure gauge or velocity meter shall be installed to monitor the pressure differential or airflow between the buffer area and the ante-area and between the ante-area and the general environment outside the compounding area. The results must be reviewed and documented on a log at least every work shift (minimum frequency, at least daily) or by a continuous recording device like the TV2 by Two Dimensional Instruments, LLC. The pressure differential between the ISO Class 7 and the general pharmacy area shall not be less than 5 Pa (0.02 inch water column). In facilities where low- and medium-risk level CSPs are prepared, differential airflow shall maintain a minimum velocity of 0.2 meters per second (40 feet per minute) between buffer area and ante-area.

The cGMP Aseptic Processing guidance also includes a section on pressure differentials and mentions the term numerous times. For example, it states that an essential part of contamination prevention is the adequate separation of areas of operation. To maintain air quality, it is important to achieve a proper airflow from areas of higher cleanliness to adjacent, less clean areas. It is vital for rooms of higher air cleanliness to have a substantial positive pressure differential relative to adjacent rooms of lower air cleanliness. For example, a positive pressure differential of at least 10-15 Pascals (Pa) should be maintained between adjacent rooms of differing classification (with doors closed). When doors are open, outward airflow should be sufficient to minimize ingress of air, and it is critical that the time a door can remain ajar be strictly controlled.

Given that cGMP expectations for pressure differentials are more stringent than <797>, it may appear that following cGMPs imposes an unnecessary burden. However, most BSCs and LAFWs are designed to achieve differential pressure and air flows that adhere to cGMP requirements, and a pharmacy simply needs to have these measurements certified twice a year to demonstrate they are compliant with both <797> and cGMPs.

Smoke Testing

USP <797> and cGMPs differ on smoke studies, but the differences are minor. For example, <797> states, In situ air pattern analysis via smoke studies shall be conducted at the critical area to demonstrate unidirectional airflow and sweeping action over and away from the product under dynamic conditions. Whereas, the Aseptic Processing guidance states, Smoke studies and multi-location particle data can provide valuable information when performing qualification studies to assess whether proper particle control dynamics have been achieved throughout the critical area. As neither document provides details related to frequency, compliance to both documents can be achieved by conducting smoke studies during initial installation and after any biannual leak test that does not meet the recertification requirements.


The pressure on hospital pharmacies to ensure compounding operations are compliant is only increasing as regulators, from state boards of pharmacy to accrediting agencies, are inspecting compounding practices and expecting compliance to USP <797> and, in some cases, cGMPs. Even hospital pharmacies that operate as 503A facilities should be cognizant of cGMP requirements. In fact, the close similarities between <797> and cGMPs related to environmental monitoring provide a strong argument for hospital pharmacists to not only educate themselves on both regulations, but also to consider implementing EM practices that achieve the aims set forth in both documents.

Airborne Infection Isolation Rooms (AIIRs) & COVID-19: Ensuring Patient Containment

Airborne Infection Isolation Rooms (AIIRs)

All U.S. hospitals should be prepared for the possible arrival of patients with Coronavirus Disease 2019 (COVID-19). All hospitals should ensure their staff are trained, equipped and capable of practices needed to:

  • Prevent the spread of respiratory diseases; including COVID-19 within the facility
  • Promptly identify and isolate patients with possible COVID-19 and inform the correct facility staff and public health authorities
  • Care for a limited number of patients with confirmed or suspected COVID-19 as part of routine operations
  • Potentially care for a larger number of patients due to an escalating outbreak
  • Monitor and manage any healthcare personnel that might be exposed to COVID-19
  • Communicate effectively within the facility and plan for appropriate external communication related to COVID-19

The following checklist highlights important areas for hospitals to review in preparation for potential arrivals of COVID-19 patients.

__Confirm the number and location of Airborne Infection Isolation Rooms (AIIRs) available in the facility (ideally AIIRs will be available in the emergency department and on inpatient units).

__ Document that each AIIR has been tested and confirmed to be effective (e.g., sufficient air exchanges, negative pressure, exhaust handling) within the last month. The AIIR should be checked for negative pressure before occupancy. If the instrument used to monitor negative pressure provides logging capabilities, it is ideal for healthcare staff to review them to verify the room stability before, during and after infected patient occupancy.

Verify each AIIR meets the following criteria:

__ Minimum of 6 air changes per hour (12 air changes per hour are recommended for new construction or renovation).

__ Air from these rooms should be exhausted directly to the outside or be filtered through a high-efficiency particulate air (HEPA) filter before re-circulation.

__ Room doors should be kept closed except when entering or leaving the room, and entry and exit should be minimized.

__ When occupied by a patient, the AIIR must be checked at least daily for negative pressure.

__ A protocol is established, which specifies that aerosol-generating procedures that are likely to induce coughing (e.g., sputum induction, open suctioning of airways) are to be performed in an AIIR using appropriate PPE.

__ Facility has plans to minimize the number of HCP who enter the room. Only essential personnel enter the AIIR. Facilities should consider caring for these patients with dedicated HCP to minimize risk of transmission and exposure to other patients and HCP.

__ Facility has a process (e.g., a log, electronic tracking, dual-purpose data logger and room pressure variable monitor) for documenting HCP entering and exiting the patient room.

__ Facility has policies for dedicating noncritical patient-care equipment to the patient.

__ Patient movement outside of the AIIR will be limited to medically-essential purposes

__ Patients transported outside of their AIIR will be asked to wear a facemask and be covered with a clean sheet during transport.

Airborne Isolation Room Specifications as per CDC

This is a single patient room equipped with special air handling (able to maintain negative pressure) and ventilation capacity. The negative pressure room is also known as an Airborne Isolation Room. This negative pressure room is usually a single-occupancy patient-care room frequently used to isolated individuals with confirmed or suspected airborne infection.

Elements of an Airborne Isolation Room 

  • Negative pressure ventilation that creates inward directional airflow from corners of the room. Ideally, this room is prefaced by an anteroom (see below)
  • The airborne isolation room should have a toilet and sink for the patient, and a designated hand washing sink for healthcare workers.
  • Have monitoring equipment including alarms; ideally an instrument capable of providing real-time feedback, current room pressure values, and alerts/alarms if pressures become unstable/unsafe. 
  • Transmit exhaust of air from the hospital room to the outside of the building
  • Recirculate air through a HEPA filter if not expelled to the outside before being returned to the general circulation
  • The door to the room must be kept closed to maintain negative pressure even if the patient is not in the room.
  • The windows in the room should remain closed at all times; opening the window may cause the reversal of airflow, which counters the benefits of a negative pressure room.
  • All healthcare providers who enter the isolated negative pressure room must be fit tested for an N95 respirator, and should take notice of room pressure to ensure that they are within acceptable ranges.
  • Only healthcare providers immunized to the organism in question should enter a room where airborne precautions are in place for varicella or measles or varicella. A respirator is not necessary for immunized individuals but is required for non-immunized workers who provide care.
  • The negative pressure room should have dedicated personal hygiene facilities including a toilet and bathing facilities.
  • One should also have a point of care evaluation for every patient interaction so that one can determine the need for additional precautions.

What is an Anteroom?

This is relatively clean and frequently used area to transition patients/healthcare workers in and out of the airborne isolation room when it is under negative pressure. An anteroom is frequently used as a transitional space between the airborne isolation room and the hallway. It is in this transition area where healthcare workers store their PPE and put on their PPE before entering the airborne isolation room. Ideally, an instrument or monitoring device will display differential pressure values between the anteroom and the Airborne Isolation Room (AIIR) as well as between the anteroom and the hallway.

  1. The laundry hamper is usually located inside the patient room.
  2. The HCP sink is usually in the anteroom location.
  3. The only items that are stored in the anteroom are the procedure or surgical masks, N95 respirator, eye protection devices, gloves, and gowns.
  4. At the hand washing sink, an alcohol-based hand sanitizer and disinfectant wipes should be available.
  5. Posters showing how to perform hand washing must be placed at the sink.

Additional Precautions – Performing Aerosol-Generating Procedures (AGPs)

  • Some procedures performed on patient with known or suspected COVID-19 could generate infectious aerosols. In particular, procedures that are likely to induce coughing (e.g., sputum induction, open suctioning of airways) should be performed cautiously and avoided if possible.
  • If performed, the following should occur:
    • HCP in the isolation room should wear an N95 or higher-level respirator, eye protection, gloves, and a gown, and ensure negative pressure is being maintained at all times via a visual indicator displaying negative pressure values.
    • The number of HCP present during the procedure should be limited to only those essential for patient care and procedure support. Visitors should not be present for the procedure.
    • AGPs should ideally take place in an AIIR.
    • Clean and disinfect procedure room surfaces promptly as described in the section on environmental infection control below.

Cautionary Statement

In most hospital Airborne Isolation Room (AIIRs), negative pressure monitoring is accomplished through antiquated and non-specific gauges like the ball in tube (Ball In The Wall), or Magnehelic gauges. These gauges offer the most basic in isolation room pressure monitoring. Caregivers relying on these antiquated instruments will not know exact pressures, have the option to monitor both negative and positive pressure differentials, receive alerts in advance when pressure levels become unsafe, no ability to view logged data, no ability to chart data, etc.

More technologically advanced instruments such as the TV2 Room pressure monitor provide patients, staff and the general public with a more comprehensive barrier of protection via an advanced alert system, visual alarms and the access to stored data points for detailed room values 24/7. With pandemics like COVID-19, patient and public safety should not be left up to chance; relying on outdated hospital equipment like a ping pong ball in a plastic tube. View a comparison between ball in the wall type instruments and more advanced, complete solutions. 

Operating room

“Ball In The Wall” Not Effective For COVID-19 Control

Controlling COVID-19: Hospitals

Very basic and antiquated devices such as the “Ball In The Wall” negative room pressure monitors are highly ineffective compared to the TV2 in preventing cross-contamination from infectious disease such as COVID-19 (Coronavirus). 

Hospitals have a monumental challenge ahead in light of the world-wide outbreak of the contagious COVID-19, otherwise known as “Coronavirus.” Now more than ever, hospitals are designing and preparing controlled environments with specialized air filtration systems (HVAC) and instrumentation to monitor differential room air pressure to reduce the possibility of cross-contamination from patients who test positive for COVID-19, or may show early symptoms of this deadly flu virus.

As with any infectious disease, hospitals typically quarantine patients in negative air pressure isolation rooms, or simply “negative pressure rooms.” This means air outside the patient’s room is maintained at a higher pressure than the air inside the patient’s room. Basically, when the patient’s door is opened by hospital staff the air will “rush” into the room, thereby preventing infected air from inside the patient’s room from escaping into the hall or adjacent room. CONTROLLING THE SPREAD OF THIS DISEASE IS VERY DEPENDENT ON THIS PROCESS WORKING AS IT SHOULD.

The anatomy of a negative pressure isolation room can be very basic, or very complex. All negative pressure rooms, however, require instrumentation to monitor negative room pressure. The go-to for many decades has been the “Ball In The Wall” which basically is a plastic tube which contains a Styrofoam ball inside. It has a small vent on either end, and passes through a wall between the controlled space (negative pressure area) and the positive pressure area.  Depending on the pressure levels, the ball will move forward or backward as pressure levels increase or decrease. About 60 years ago, this was a sufficient solution, because it was the ONLY solution.

These “ball-in-the-wall” devices are not only very inaccurate, but do not provide ample notification when and if a controlled environment becomes compromised. In essence, this means if a negative pressure room becomes compromised because of an air lock leak, HVAC issue, electrical problem, etc – then every single patient, and all staff in the hospital are at risk of contamination.

Alternatives Are Mandatory

Technology is accelerating at an incredible rate. No one knows this better than the healthcare industry; they usually take full advantage of technological advancements in order to provide more comprehensive patient care and safety. But using the ball in the wall is an exception to this rule. Some hospitals and treatment centers are still relying on age-old devices like the ball in the wall to prevent the spread of infectious disease. A tube containing a Styrofoam ball is in no way precise enough to provide protection against the spread of disease; especially if on one side of that wall there is a patient with a communicable disease or virus like COVID-19.

One such alternative would be to integrate stand-alone digital differential room pressure monitoring instruments. Ideally, these devices would be able to immediately and simultaneously alert staff, facilities managers and caregivers if conditions inside an isolation room become critical. Local alarms (in-the-room high decibel alarms), immediate automated emails sent to staff, and SMS messages sent to caregivers would help to provide immediate quarantine protocols. With ball in the wall type devices, if no one is looking directly at it – they have no way of knowing if there is an issue. In the case of potential contamination, every millisecond counts.

As technology advances, costs decrease. What may have once been a barrier for adoption due to cost, is now no longer an issue. In fact, there are many products on the market which provide a high level of advanced warning and monitoring for patient isolation rooms, and are cost equilivant to ball-in-the-wall type products.


The CDC is warning all healthcare facilities to immediately revise protective policies and procedures to prepare for what is expected to become a wide-scale pandemic. A great start for healthcare providers on the road to ensuring public safety would be to take inventory of any and all controlled environments, isolation rooms, cleanrooms, etc… and note which of those controlled spaces are relying on ball in the wall type of room pressure indicators.

We at Two Dimensional Instruments have created a comparison showing features of a completely digital-based early warning monitoring system for room pressure as compared to a ball in the wall type of monitor. In this comparison, a “TV2 Cleanroom Monitor (TV-202)” was compared to the “Ball-In-The-Wall” brand of ball-type room pressure indicators/monitors.

All other features aside, perhaps the most important point of differentiation between the TV2 and the Ball In The Wall is the ability to not only receive advanced email/SMS alerts when conditions are unfavorable, but also the ability to log, chart and store all data points. This means you’ll never have to guess what the status of the room is/was at a given point in time. The TV2 Room pressure indicator can store over 80,000 data points (about 2 years worth if logging every 10 minutes) and can be exported in excel format.

Call us today to see why the TV2 Room pressure Monitor is the best pressure indicator for your hospital.

Call now: 877-241-0042




Gowned lab worker working in hood area

Modular Cleanrooms

Cleanrooms are basically controlled spaces where particulate counts, temperature, relative humidity and pressure are controlled and monitored. While movies and the sci-fi genre may make these spaces seem very high-tech, they are actually quite basic in design and function. In fact, you can transform almost any existing space into a cleanroom, although the cost of doing so be quite high.

For companies who plan on completing short-term projects or production runs with specific products who do not have a working cleanroom, using a modular cleanroom, also known as a “portable cleanroom” can be a viable alternative.

Modular Cleanroom Benefits

A modular cleanroom can provide many benefits. The primary benefit is cost with flexibility and portability of processes following as a secondary benefit.  Below are just a few of the possible benefits of choosing a modular cleanroom over a “built-in” option.

Versatility: Most modular cleanrooms can be assembled on-demand, and be ready to use in a couple of days. These are generally complete solutions requiring no ancillary expenses.

Flexibility: With portable cleanrooms, the customer can benefit from nearly unlimited floor-plans and layout options; adhering to what makes the most sense for a particular process.  Alternatively, re configuring a built-in cleanroom to change the layout or design would require stopping processes and heavy construction costs.

Cost-efficient: A modular cleanroom is manufactured offsite; and can be custom built. They often cost a fraction of what permanent cleanroom construction would cost.

Renting and leasing: Most portable cleanroom builders have options to lease or rent the portable cleanroom. This makes sense for companies that know they have a short-term project.  They can rent or lease a cleanroom for a short term and then return it if they need something different for the next project.

Tax break: Since a modular cleanroom can be easily disassembled and is completely portable, and moved to a different location within the company, it is considered a piece of capital equipment; benefiting from the same tax regulations as other machinery and capital equipment.

Cleanliness: For cleanroom classification requirements of ISO 6 and above, a modular/portable cleanroom can be the better option; the materials used in modular cleanrooms do not face the same material degradation challenges faced with permanent cleanroom construction.


Types of Modular Cleanrooms

Hard wall Modular Cleanrooms: These portable cleanrooms are typically designed and built to customer specifications. They are delivered on-site and installed/assembled by a manufacturer representative. Hard wall modular cleanrooms are typically built using vinyl, aluminum, fiberglass or a combination of these materials. They can be configured with windows and doors placed according to the buyers specification.  They typically come complete with monitoring solutions for particle counts, temperature, pressure, and relative humidity. It is important to note, however, the monitoring instruments included in modular hardwall cleanrooms may not always be top-of-the-line, so it is important to consider using a third party, stand-alone solution for more accurate monitoring. Also included are HEPA filtration units that can be configured to meet ISO 5 – ISO 9 standards, in most cases.

Soft-wall Modular Cleanrooms: These are the most portable of all modular cleanroom designs. Customers can typically select the thickness of the plastic sheeting/enclosure, the level of filtration (and in some cases they can be outfitted to tie in to existing HVAC systems). The plastic sheeting is usually mounted on steel or aluminum frames complete with casters. While soft-wall modular cleanrooms offer the highest in portability factor, they may not reach the same cleanliness levels that hard-wall modular cleanrooms can. It all depends on the manufacturer and the cost the buyer is willing to bear.



Perhaps the greatest challenge with any cleanroom, but particularity with a modular cleanroom, is maintaining mandated cleanliness and keeping the overall environment consistent. The best way to avoid contamination is to have an accurate particle counter on site, or to have your modular cleanroom bench tested regularly. Just as important as particulate counts and air exchange rates is maintaining air quality.  This generally means pressure, temperature and humidity. To monitor and maintain air pressure, temperature and relative humidity, a stand-alone cleanroom differential pressure, temperature and relative humidity monitor is essential. Differential pressure is what keeps pollutants out of a standard cleanroom (or keeps caustic chemical fumes and particles in when using a negative pressure isolation room). These highly precise cleanroom monitors are relatively inexpensive, and can be easily attached to your portable modular cleanroom. A number of these are available, each of which have different features.  Always check if the instrument you choose can alert local staff, as well as provide advanced alerts via SMS, email and/or automated phone calls.

Early detection in air quality issues will save a great deal of potentially lost time, money and contamination remediation.




Gowned lab worker under hood w TV2 on Wall

Clean Room Design & Build


Industrial Applications
Process Classification
Aerospace ISO Class 5-7
Assembly of Touch Screen ISO Class 7
Composite Materials ISO Class 8
General Industrial ISO Class 8
Injection Molded Parts ISO Class 7-8
Optical ISO Class 5-7
Process Classification
Semiconductor ISO Class 5
SMT Assembly ISO Class 7-8
Solar ISO Class 5-7
Wafer Board ISO Class 5
Consumables and Pharmaceuticals
Application Classification
E-Liquid ISO Class 7-8
Food Packaging No Classification
Nutraceutical Packaging ISO Class 7-8
Pharmaceutical Compounding ISO Class 7
Pharmaceutical Packaging ISO Class 8
Sterile Compounding ISO Class 5
Medical Devices
Application Classification
Device Reprocessing ISO Class 7
Inplantable Devices ISO Class 5
Medical Device Packaging ISO Class 7-8

Building and designing a cleanroom requires proper planning, and a thorough understanding of the equipment and technology used in the controlled environment to ensure it’s correct and safe operation. Clean room design will be heavily dependent on the type of process that will be carried out in the space chosen.

Many companies prefer to consult with an engineer, an architect, an HVAC specialist and a general contractor before moving forward with a particular clean room design.

For the purposes of this article, we’ll get right down to the basics of best practices for optimal clean room design.
























ISO 14644-1 Cleanroom Standards
Classification Maximum Particles/m3 FED STD 209E Equivalent
≥0.1µm ≥0.2µm ≥0.3µm ≥0.5µm ≥1µm ≥5µm
ISO 1 10 2.37 1.02 0.35 0.083 0.0029
ISO 2 100 23.7 10.2 3.5 0.83 0.029
ISO 3 1,000 237 102 35 8.3 0.029 Class 1
ISO 4 10,000 2,370 1,020 352 83 2.9 Class 10
ISO 5 100,000 23,700 10,200 3,520 832 29 Class 100
ISO 6 1.0 x 106 237,000 102,000 35,200 8,320 293 Class 1,000
ISO 7 1.0 x 107 2.37 x 106 1,020,000 352,000 83,200 2,930 Class 10,000
ISO 8 1.0 x 108 2.37 x 107 1.02 x 107 3,520,000 832,000 29,300 Class 100,000
ISO 9 1.0 x 109 2.37 x 108 1.02 x 108 35,200,000 8,320,000 293,000 Room Air
Exterior view of hospital

Seattle Children’s Hospital: Preventable Disaster?

In May 2019, Seattle Children’s Hospital faced an emergency situation where 14 surgical rooms were forced to cease operations, with over 3,000 families potentially affected by deadly Aspergillus mold exposure. The Seattle Children’s hospital was forced to move or reschedule over 1,000 surgeries. Unfortunately, one patient recently died in 2018 after developing an infection as a result of exposure to this type of mold. Many more could face ongoing health complications.

How this could happen in this modern age of technology, to a hospital which, in 2019, U.S. News & World Report named one of the 10 best children’s hospitals in the country? In fact, U.S. News & World Report has recognized Seattle Children’s as a top children’s hospital every year since it began ranking medical facilities more than 25 years ago.

The looming question is “Was this tragedy preventable, and, if so, what should have been done?”

Who’s at fault?

According to the Centers for Disease Control and Prevention, Aspergillus is a common mold found both indoors and outdoors. Unless you live in a cleanroom or isolation room, you have most likely inhaled millions of it’s spores into your lungs every day since your birth.

While most people breathe in these spores every day without getting sick, the mold poses a real risk to those with compromised immune systems or lung disease. Mold growth can be accelerated and concentrated in man-made surroundings whereas in natural environments, the concentrations are diluted to just a few parts per million by global atmospheric conditions.  The way to prevent these spores inside closed spaces like operating rooms and patient rooms inside hospitals is to carefully monitor pressure, temperature and humidity.  As long as temperature and humidity are maintained a proper levels mold can not grow and if positive pressure is maintained the spores will, for the most part, be kept outside the area.

Aspergillus, and mold in general, can cause allergic reactions and infections in the lungs and other organs in the body. This is precisely why hospitals must monitor and manage mold growth of any type – patients in the hospital (children and elderly) are already at a greater risk for adverse effects of mold growth; even more so if they have existing health complications and compromised immune systems.

With that said, the Seattle Children’s Hospital had known deficiencies in room air purification systems. The patient who recently died (2019) contracted the Aspergillus mold infection a year ago.  That was known at the time and should have been a wake-up call to install equipment to monitor conditions to prevent a re-occurrence.  It is unclear which, if any, preventative or remediation processes were put in place after the first known incident. It is known, however, that they were largely ineffective in preventing further growth; the mold was still present a year later.

Ultimately, the Seattle Children’s Hospital is at fault – mold and other potentially harmful pollutants, of natural or synthetic origin, must be controlled no matter the cost.

What could have been done

There are dozens of monitoring systems available to hospitals, and some even provide advanced alerts when relative humidity and temperature levels become ideal for mold growth. These systems can allow for immediate correction of dangerous conditions.  An alert delivered in a timely manner can help maintenance personnel make adjustments to the HVAC systems and initiate clean-up measures to get rid of the mold.  Carefully monitoring potentially contaminated areas is a must for every health care provider.

Experts agree that having multiple environmental monitoring systems in place is a good idea; one tied in with a building management system, and another stand-alone as a fail safe. It is also important to note that any system which requires an employee to physically view a monitor or screen can only be as effective as the person viewing it. A better alternative is a system which includes a digital display of current values, offers a room or local alarm system when level are outside set ranges, and has the ability to notify key personnel via SMS, email and/or automated phone calls when issues of air quality occur. Many of these systems are specifically designed for hospitals, and include options to monitor both negative and positive pressure isolation rooms – helping to reduce exposure to mold and cross contamination.

Although there are only a handful of manufacturers that offer such comprehensive systems, they do exist, and are a fraction of the cost of having an incident like the one at Seattle Children’s Hospital. In fact, if you look at the math, a hospital could buy a comprehensive monitor for about the same cost it takes to operate a surgical room  – for 7 minutes.


Bottom line, there are no excuses. Hospitals operate on a tight budget, and have ongoing issues with accounts receivables from patients and insurance carriers. There are huge fees to surgeons, malpractice insurance, and other costs to operate a modern and efficient hospital.  However this is no excuse for overlooking something as basic as providing a mold free environment.  A piece of equipment as inexpensive as a modern advanced monitoring system to prevent mold growth and provide critical data on the health of the environment.  This solution does and will continue to have a huge impact of patient health and the ability to recover from surgery and the issues that brought the patient to the hospital in the first place.