Ball In The Wall Alternative For Patient Safety

Why using Ball In The Wall, and other yes/no pressure indicators could result in serious liability and health consequences. 

Patient safety is a top priority for healthcare providers and organizations. However, many hospitals are still relying on antiquated equipment (such as ball-in-the-wall type devices), which do not quantify pressure.  They only indicate whether a positive or negative pressure exists.  This results in a decreased ability to protect the health and wellness of both patients and staff.  Federal standards are written to require specific pressures in certain areas.  For example, anesthetizing locations should have higher pressures than adjoining rooms and corridors to ensure that contaminated air does not enter the area. Isolation rooms need a lower differential pressure to ensure that contaminated air stays in the room.

A great example of this (and some of the most important rooms in the hospital) are surgical suites and patient isolation rooms. In these critically controlled environments, it is imperative that hospitals use the most cutting-edge technology and equipment available, to ensure and verify that ‘bad air’ stays where it is supposed to. In this article, we will discuss the pro’s and con’s of using ball in the wall type pressure monitoring devices.

Surgeon and cleanroom worker

Surgeon prepared for surgical room (left) and Cleanroom worker in “bunny suit” (right)

Surgical Rooms: Positive Room Air Pressure

Surgical rooms must be cleanrooms. An OR, is a “controlled air environment” using a combination of ultra-clean procedures, clothing and sterilization and air handling processes to keep them as clean as possible. Most likely you’ve seen pictures of cleanrooms where the workers are wearing white “bunny suits.”

A surgical suite is essentially the same thing. Of all the processes and protocols in place to protect patients from infection during surgical procedures, probably the most important component to keeping a surgical room clean is the equipment to maintain positive air pressure at all times. Unfortunately, many hospitals still rely on outdated devices like a ball in the wall to ensure the room is properly pressurized.

Most hospitals have state-of-the-art air filtration and pressurization systems that keep surgical rooms at a specific positive pressure at all times. Positive pressure in a surgical room means the air inside the surgical theater is higher than exterior rooms. In fact, any time you open the door to a surgical suite, you should feel a “rush” of air coming out of the room.

This positive air pressure differential ensures the room stays clean by preventing any outside air form entering the room. Outside air may contain contaminants such as dust, viruses, bacteria, mold, etc. These are all dangerous particles to have in the room while a patient is being operated on. Equally important is monitoring the air for temperature and relative humidity (RH). If the temperature and humidity is too high, you have an environment ripe for mold, bacteria and mildew. Additionally, keeping staff cool and as sweat-free as possible keeps the environment safe.

Isolation rooms: Negative Room Air Pressure

Negative air pressure room with ball in the wall indicator

Negative air pressure isolation room (ball in the wall air pressure indicator above doorway)

A patient isolation room (negative air pressure isolation room) is designed to perform the opposite function of the surgical room. Instead of keeping the air pressure higher than the outside rooms as with a surgical room, a patient isolation room is designed to maintain a lower air pressurization than the exterior room(s).

The reason for this is to keep communicable diseases, hazardous medication residues, viruses, bacteria, and patient illness inside the room; thereby keeping it contained. When you open the door in a patient isolation room, you would feel air “rush” in to the room. The COVID-19 (Corona Virus) outbreak has increased awareness of hospital employees to the importance of maintaining a negative pressure area to prevent the spread of the virus.

If the HVAC system, air locks, procedures and protocols in place are all operating as designed, these rooms can save lives by  limiting unintended exposure to communicable disease.

It is widely known and accepted, however, that equipment can fail, parts wear out, and most of all – humans make mistakes. In critical environments like negative pressure rooms and positive pressure rooms the monitoring of these systems can not be left up to outdated instruments and protocols.

Monitoring Positive & Negative Room Pressure With Ball In The Wall

Ball In The Wall In Surgical Room

Pictured is a “Ball In The Wall” type instrument used in surgical rooms / positive pressure rooms.

At the time of writing this article, there are literally thousands of hospital surgical rooms and patient negative pressure isolation rooms still using outdated instruments to make sure pressure is maintained at safe levels. Since we now understand the importance of keeping rooms properly pressurized, we can agree that it is just as critical to monitor pressurization level at all times.

The most widely used (and severely outdated) device to monitor pressure is a plastic tube with a Styrofoam “tennis ball” inside. If the room has positive pressure, a green ball will be “pushed” to the other end of the tube which passes through the wall of the surgical room into the gowning area (where surgeons get dressed, wash hands, etc.). For negative pressure isolation rooms, the ball inside the tube is “red.”

These ball in the wall devices sound simple, right? No electricity, no technology to learn, what can go wrong…?

As it turns out, a LOT can go wrong. Ball in the wall devices have many shortcomings. The most important of which is the fact that they can not indicate the pressure they ‘see’.  They can only tell you that some pressure differential exists. This is not enough.  Too little pressure can still allow contamination and definitely indicates that some part of the environmental system is not working properly. A clogged air filter, for example, could be preventing enough air from entering surgical area to prevent contamination.

Below we list have listed some pro’s and con’s, along with what an similarly priced instrument that does a much better job of ensuring environmental standard are met.

Ball In The Wall: Pro’s

Does not require electricity. In the event of a power outage, it will still function.

Does not require any technical expertise to install, or operate. As long as you are not color blind, you can see if the pressure is roughly positive or negative.

Ball In The Wall: Con’s

X Only provides an overall “yes/no” regarding pressure. Caregivers and staff won’t know how little or great the pressure differential actually is.

X No advanced warning when pressure starts to drop/increase.

X No data stored to verify when pressure started increasing/dropping.

X No charting capability to see historic drops or increases in pressure.

X No way to alert necessary staff by email/SMS/automated phone dialing.

X No ability to set custom maximum/minimum threshold points for alarm.

X Only a few models have local audible alarm capabilities.

X No external relay to be triggered when threshold levels are exceeded (i.e. switching on auxiliary HVAC, closing a vent, sounding remote alarm, locking an isolation door, etc.).

X No visual data on exact room conditions.

X No ability to monitor temperature.

X No ability to monitor relative humidity (RH).

X No ability for single instrument/ball in the wall to measure both positive and negative room air pressure.

X No ability to monitor multiple rooms for positive/negative air pressure simultaneously.

X No storage of data points.

X No LAN/WiFi connectivity.

X No means to quantify measured values.

X Requires invasive drilling and installation which can potentially open room to minute air leaks.

Monitoring Positive & Negative Room Air Pressure With TV2: Pro’s

TV Cleanroom Monitor / Room pressure Air Differential Monitor

The TV2 Room Air Pressure Differential / Cleanroom Monitor featuring touchscreen display, advanced alerts via email/SMS, multi-room remote monitoring…and more!

Modern positive and negative room air pressure monitoring devices such as the TV2 Room Pressure Monitor have many advantages over ball in the wall devices. Below are pro’s and con’s of using this advanced instrument to keep patients and caregivers safe and meet federal safety standards.

Monitor both positive and negative room air pressure with one device.

Monitor up to four rooms for positive/negative room air pressure with one device.

Constant display of actual pressure measurements to within 0.007″ wg.

Color coded display showing safe/unsafe conditions.

Local audible alarm.

Sends email, SMS (text) alert to multiple departments/staff if conditions become unsafe.

Ability to monitor temperature and relative humidity in addition to pressure.

Remote sensor placement as far away as 200-feet.

External relay to trigger an action when threshold levels are exceeded (i.e. switching on auxiliary HVAC, closing a vent, sounding remote alarm, locking an isolation door, etc.)

User-programmable alarms.

User-set alarm delay times to eliminate false alarms (i.e. opening door, closing door, etc).

Real time room pressure, temperature and RH updated every 4 seconds.

Monitoring differential air pressure in hospital without ball in the wall

The TV2 can monitor locally, or remotely, meaning staff can view positive/negative pressure conditions in all patient rooms from one centralized location.

Password protected menus to prevent changing settings.

Ability to download several of logged data points (over 80,000) for room air pressure, temperature and relative humidity – if there is ever an issue, data is readily available for industry oversight organizations and inspections.

Connectivity to LAN, WiFI, Ethernet.

Comply with  ISO 14644, 21CFR11,CDC, FDA, JCAHO & <USP 797> and <USP-800> requirements.

Will continue to log, chart, record and display room pressure, temperature and relative humidity for up to 72 hours without external power.

Each sensor is calibrated and accompanied by a renewable (2-year) NIST traceable calibration certificate.

Extremely accurate representation of real-time room air pressure differential conditions: Differential pressure sensor ±0.50″wg (±0.007).

Can log pressure, temp and RH every 60 seconds or as seldom as once every 24 hours.

Can be mounted in box, industrial instrument case, or flush-mounted on wall.

USA designed, assembled, and supported with live, USA-based customer support.

Provides immediate alerts when pressure drops/increases even a fraction of a Pascal/”WG.

FREE FOREVER secure software, support and updates.

Monitor for positive and negative room pressure

TV2 monitoring positive/negative room air pressure, temperature and relative humidity (box mount option shown)

Monitor locally in room, or remotely from nurse station and/or facilities management. The TV2 Pressure Monitor can be accessed on smart devices, tablets or PC on the LAN, so no matter where you are, you can view a specific room or several rooms – and the current (accurate) positive or negative pressure level in each.

The above features were specifically designed in cooperation with the country’s best engineers, system designers, healthcare leaders and end users – to ensure patient safety and the highest level of monitoring for positive and negative room pressure in hospitals. Accuracy, dependability and advanced warning when it matters most.

Monitoring Positive & Negative Room Air Pressure With TV2: Con’s

X Requires about 1 hour for installation

X Requires about 30 minutes to become familiar with interface and menu system

Ball In The Wall vs TV2 Cost

For features, safety, reliability and accuracy – nothing beats the TV2 Room Pressure Monitor / Cleanroom Monitor. The ball in the wall doesn’t even come close. In regards to pricing, however, the ball in the wall does beat the TV2 Room pressure Monitor – only not in a favorable way to the healthcare provider. Here’s a quick snapshot of pricing:

Areas Monitored for Room pressure Ball In The Wall Pressure Monitor Price TV2 Room Pressure Monitor Price
Cost to monitor one room for pressure $1,165.00 $1024.00
Cost to monitor two rooms for pressure $2,330.00 $1740.00
Cost to monitor three rooms for pressure $3,495.00 $2,248.00
Cost to monitor four rooms for pressure $4,660.00 $2,781.00

Even More…

The TV2 Room Air Pressure / Cleanroom monitor is a trusted instrument, and is used by some of the world’s most well-known and admired companies: NASA, GE Industrial, Northrup Grumman  GE Global Research, BIC Corporation, GE Aircraft, Stark Aerospace, Lockheed Martin, ARMY, NAVY, Johnson Controls, State Department, Homeland Security, Boston Heart Laboratory  Coast Guard, Boston Scientific, NY Presbyterian Hospital, and more. 

In healthcare, we are very-well known and trusted; our customers include: VA Hospital – Southeast Louisiana, Valley Baptist Medical Center Greater Lawrence Family Health Center, Santiam Memorial Hospital, Senderra RX, San Juan Public Health Services, Multnomah County Hospital, Nebraska Public Health, Arkansas Public Health Clinics, Hackensack & University Med Centers, Episcopal Church Home, American Retirement Corporation, Triad RX, Cottage Hospital, NY Presbyterian Hospital, U of IL Scientific Research hospital, Navy Reserve Center, Corpus Christi Health Center, Huntington Beach Hospital, 161st Medical Group, Barnesville Hospital, Davita Medical, Specialty Scripps Pharmacy, St Luke’s East Hospital, Alan Bates Medical Center, Florida Health Care Plans, Arkansas Health Clinics, Sentara, Branch Medical Group, St Luke’s South Surgery Center, Cal Poly Kinesiology & Public Health, Karl Storz Imaging, Biotech Remedies, U of Delaware – Health, Orlando Health Care


For information on the TV2 Cleanroom Monitor / Room Air Pressure Monitor, view full product page here, or call 877-241-0042 or use the contact form here.