Application Case Study: Pressure Monitoring for NFPA Gas Cylinder Protection

Application Case Study:  Pressure Monitoring for NFPA Gas Cylinder Protection

If readers ever need a reminder that workplace accidents can occur at any time, from any source, without warning, breezing through the OSHA Catastrophic Accident database will surely do the trick.  Responding to an uptick in accidents involving compressed gas cylinders, this is exactly what one of our long-time distribution customers did in searching for ways that they could help reduce their end-users’ risk. 

This distributor provides industrial compressed gases in cylinders and bulk containers, along with their own value-added safety and handling equipment.  Hearing from their end users that most near-miss accidents involved unexpected gas pressure and flow, the distributor set out to add pressure monitoring and protection solutions to their catalog, which brought them to Whitman Controls for help selecting instrumentation that fit the bill. 

The goal was to define and develop NFPA-inspired automated solutions, but first, we had to further define the problems and use-cases in play, making this an interesting exercise in safety risk assessment before getting to the controls piece.         


About Us

As a veteran-owned small business, Whitman Controls is dedicated to supplying premium quality, reliable, technologically advanced instrumentation for use in nearly any application.  Our Bristol, CT manufacturing facility embodies over 40 years of engineering, fabrication, and customer service expertise, serving both end-user and manufacturing customers nationwide through direct and distribution channels.  


Application Summary 

Industrial gases and cryogenic fluids are vital resources used across countless applications, from metal working to transportation, medicine to food service, and so on. 

Most users receive these gases in high pressure cylinders, holding up to 500 cubic feet of gas compressed between 150 and 6,000 PSI.  Given these volumes and pressures, compressed gas cylinders can pose significant risks should they leak or rupture, which could expose nearby personnel to their hazardous gaseous contents (such as oxygen, propane, nitrogen, ammonia, or acetylene), not to mention potentially launching the cylinder like a projectile. 

The National Fire Protection Agency (NFPA) publishes a technical code document known as NFPA 55 that governs the use and handling of these compressed gas cylinders.  This code, and others like it, drive continued development of safe practices, robust protective equipment, and automated distribution systems across industries, all intending to remove employees from harm’s way and catch potential hazards before they can cause damage.



Our client engaged us to assist with identifying hazards involved with compressed gas cylinders that together we could automate away, using NFPA 55 requirements as a guideline.  In a group working session, our combined teams came up with three main hazard categories that could be monitored by instrumentation:

  1. Changeover Injury – physically handling cylinders is the main source of injuries and accidents involving compressed gas cylinders, leading to smashed toes, crushed fingers, or worse.  
  2. Media Release – since cylinders are kept at such high pressures, gases stored within can easily be released through tiny leak points in the container or connected distribution piping, as well as when disconnecting a cylinder for swap-out.  Released gases can quickly spread into surrounding areas, creating hazards of asphyxiation, chemical reaction, contact burns, fire, and combustion.  
  3. Proper Operating Pressure – while cylinders store their contents at very high pressures in order to squeeze in more mass, pressure regulators are used to deliver gases at lower pressures out to their connected systems.  If these regulators fail or are set incorrectly, too high of a gas pressure can be sent downstream, leading to distribution equipment failure and injury.  Likewise, filling cylinders over their limits can be dangerous as well.     

With these hazards identified, the next step was to figure out how to add automated solutions to the client’s existing lineup of NFPA 55 Cylinder Storage Cabinets, solving multiple risks at the same time.  


“We’re dealing with literal pressure rockets and deadly chemicals, and we’re delivering these to users who might not be fully aware of all the issues they could be getting into [handling compressed gas cylinders].  To help keep everybody safe, we wanted to offer automated filling and distribution gear along with our NFPA 55 storage cabinets, and Whitman’s engineers got us there.”  - Regional Sales Manager, Confidential Industrial Gas Distributor 



Digging into the three hazards identified above, we systematically reviewed the hydraulic variables involved in each and concluded that pressure monitoring could successfully manage each one.  

For Changeover Injuries, the key here was to reduce the amount of cylinder handling events required.  To achieve this, Whitman and the distributor developed an automatic changeover system that would switch between multiple connected cylinders, greatly reducing the need to manually swap cylinders.  

For Media Releases, we determined that monitoring for small but steady pressure changes occurring in a different pattern than normal was the key.  We developed a pressure monitoring system that would be trained on normal operating pressures, and would automatically close valves and sound an alarm upon deviation from that pattern.

For Proper Operating Pressures, the solution here was to add pressure monitoring, flow and pressure control valves, and emergency relief and isolation valves.  In our research, one of the main root causes of over-pressure situations was found to be poorly maintained mechanical pressure regulators, which we could catch before failure with a few sensors and fast reacting shut-off valves.      

In all cases, we landed on the Whitman J205G Pressure Sensor as the instrument of choice.  We assisted our client with programming settings, control loop profiles, and general integration support, and they deployed these sensors in piping manifolds tied to safety controllers mounted alongside their NFPA 55 cylinder storage cabinets.   



There is no substitute for proper employee safety training, controlled procedures, and ongoing refresher coaching.  Automated safety systems are only intended to supplement operator awareness, care, and sound decision making. 

Anywhere that we can remove operators from potential hazards using automation helps reduce the likelihood of an accident, but in no way removes the responsibility of operators and management to make sure everyone makes it home safely every day.  A

fter this project, our customer has deployed dozens of NFPA 55 gas cylinder safety cabinets with our automated monitoring systems, and no safety accidents related to gas cylinders have been reported from any of these facilities since.  


Data Bullets 

  • 80% increase in client safety cabinets sold with automated safety add-ons
  • 0% reported end-user incident rate after deployment of these safety add-ons 
  • 1-2 weeks’ lead time on Whitman J205G pressure sensors 
  • 85% reported end-user early hazard detection using automated safety pressure monitoring  


Here at Whitman Controls, our values drive us to provide the highest level of servant partnership that you can find.  To discuss your applications or to learn more about our capabilities, please contact us at (800) 233-4401, via email at [email protected], or online at