Working with Fire Suppression

While fire suppression systems (FSSs) are intended to protect people and property, they can pose dangers to people who depend on them — and the actions of people can keep these systems from providing the intended protection. Consider these three goals for working where FSSs are present:

1. Being safe in a fire suppression protected room (FSPR).

2. Keeping the FSS safe from acts of workers.

3. Ensuring the FSS can and will do its job.

4. “Fire suppression system” doesn’t mean a standard sprinkler system. It means a system that automatically disperses a fire suppression agent such as foam, carbon dioxide, a dry chemical, a wet chemical, or a dry powder. See NFPA Standards for Fire Suppression Systems for the applicable NFPA standards.

There are also water-based FSSs that are like sprinkler systems but have important differences. These are less relevant to the first goal than the other types (water-based systems won’t asphyxiate you).

Working in An FSPR

An FSPR can be anything from a large backup generator room to a closet-sized space that is part of process equipment. If you don’t know what type of system the FSPR has, assume it uses a gas to smother the fire (and, potentially, you) until you can verify otherwise.

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Numerous types of fire suppression systems are in use today (kisgorcs/iStock/ Getty Images Plus).

An FSS needn’t be in a room to pose a hazard. For example, a varnishing oven might have an FSS that consists of a bank of CO2 bottles and a dispersal system. If the FSS is activated, CO2 will hit the oven at key points, and local levels of CO2 will rise. Though you aren’t in a closed room, you could still be overcome by CO2. If it’s enough to just make you dizzy, you could fall onto hot equipment or fatally strike your head. Think of this open area as an FSPR without doors — still dangerous, just to a lesser degree.

Most facilities have an access policy for FSPRs. Facilities with a non-enclosed FSS (as in the varnishing oven example) may not have an access policy for the protected area for practical reasons.

Follow these tips to be safe in an open or closed area protected by an FSS:

• Before entering, notify the person in charge of that area. Let that person know when you intend to enter, why you intend to enter, what you intend to do, and when you intend to exit. Sign in, and/or ask to be monitored. Ask about extraction procedures; how will you be removed to safety if you are overcome by the FSS?

• Update your supervisor with the notification and any feedback or requirements from the person in charge of the area.

• Before entering, take note of the “lay of the land.” What could block your exit, and is there an alternative exit to the entrance you are using?

• Once you’ve entered, look for any emergency exits and (if applicable) emergency communications gear. In addition, look for panic buttons, local alarm shutoff control(s), and anything else you might be expected to use or operate during an emergency.

• Evaluate the noise level in the room or area. Would it prevent you from calling for help? Would it prevent you from hearing an audible alarm? Would you be unable to see the warning light(s) due to how your body is situated when
working? In any of these cases, you should probably have an attendant who is in line of sight of warning light(s). One solution that can easily be designed into both FSPRs and FSS-protected open areas is the presence of multiple warning lights aiming from multiple directions in a “you-can’t-miss-this” fashion. With today’s advanced LED lighting systems and controls, it’s possible to take this idea up a level — or three.

• Check the FSS. You want to ensure that you are protected from it, and there’s not a problem preventing it from providing fire suppression. So, for example, you’re visiting that varnishing oven with its bank of CO2 bottles. Read the dates on the inspection tags. Notify your supervisor if there’s a problem.

If it’s an enclosed room, these additional precautions apply:

• Don’t block the door open. If you find the door is already blocked open, don’t enter. Report the problem to the person in charge of the room and to your supervisor. They must determine whether the door should remain open and whether it’s safe for you to enter. Enter the room only after they give you the green light to do so.

• Are any emergency exits blocked by items that are in the exit path? Are machines or equipment installed such that you must climb over them to reach the exits?

• Look for panic bars and chains used on the same doors. This is a sign something is wrong; notify your supervisor immediately.

• Don’t attempt to fight a fire that flares up in an FSPR. That’s the job of the FSS. Make a hasty exit, and notify the person in charge of the room.

Protecting the FSS from People

FSSs protect people and property if properly installed and maintained — and if not defeated by well-intentioned acts of the people working around or on them.

In the varnishing oven example, a given maintenance procedure might require temporarily disabling the FSS to protect the worker performing preventive maintenance.

Consider a task like calibrating the temperature control loops. If simulating the full temperature range will give a high-temp signal to the FSS, you’d get an unintended discharge of the FSS. This would create a hazard for the worker while also rendering the FSS unable to perform until its CO2 bottles are replaced.

Or let’s say the FPS uses foam. That creates a mess, plus the system will probably need a refill.

You may not have a big red sticker on your PM procedure telling you that doing X will activate the FSS. So, before working on anything associated with an FSS-protected area, determine whether your work could trigger activation of the FSS.

If so, you will probably have to perform a lockout/tagout on the FSS equipment (and related circuits) in addition to the equipment you are working on. This kind of lockout/tagout must be coordinated with the person in charge of the room or area.

That means a job briefing with that person, detailing such things as who will be doing the work, what the work will be, and how long it will take.

You checked the FSS before starting the job. Now check it again before leaving. Maybe you had to lockout/tagout equipment that allows the FSS to detect and respond. Are you sure everything is back in working order? How can you verify this? Also, if you notified your supervisor about a problem at the outset (e.g., expired dates on bottles), make another inquiry about the status of that.

Ensuring the FSS Can Do Its Job

These systems are typically designed to protect specific spaces. Altering those spaces is one way people inadvertently cripple, or even defeat, these systems.

A misting-based FSS in an appliance factory failed to quickly extinguish a fire because materials had been stacked between the dispersal heads and their targets. In a data center, doors to a battery room were blocked open; this allowed the CO2 to escape instead of occupy the space and smother fire.

In another plant, boxes had been placed too close to an oven that was FSS protected. The FSS should have extinguished the fire but failed to do so; the fire was extinguished manually. This caused a problem when reporting the incident to the insurer, because the required photos of the CO2 maintenance tags showed half the bottles were more than a year past their expiration date.

For these systems to protect people and property, they must be maintained as instructed by the manufacturer and/or the insurer. Even if they are, however, many kinds of seemingly harmless acts can cripple or defeat an FSS. If you’re working around an FSS, be on the lookout for the results of such acts. Yes, the life you save may be your own, but you may save many others, too.