I was wondering if there were any regulations about the manual pull stations that are required to be located outside of a room that is Halon protected. The reason I ask is because I was informed that at my facility, once the manual pull station outside of the Halon Room is pulled, the Halon is immidiately dumped with no delay. That system seems a bit dangerous to me especially if anyone is in the room that may not be visible and someone pulls the station. So what I am directly asking is if anyone know whether or not there must be a delay for the Halon dump from a manual pull station. I have searched OSHA, NFPA, Manufacturer and nothing is mentioned but I was wondering if anyone would know exactly where I could find that info and what it states. Thanks to all in advance.

futureCIH,

This is one of these topics that is so fundamental, it may not be mentioned. Use the Hippocratic oath, "First, do no harm." NFPA, OSHA and all other groups have an implicit assumption that your safety systems will not kill, injure, or exacerbate a hazardous situation.

The first thing I would do would be to calculate if an oxygen deficient atmosphere (<19.5%) can be created. The design plans for the system may already have that information. Second, I would determine if a ceiling limit for inhalation can be reached. Third, determine if any other hazards can be created (dizziness, obscured vision...)

If any of these can occur, I would recommend installing an alarm with a 15 second delay. When the station is pulled an alarm sounds and a timer begins. After 15 seconds, the Halon is discharged.

MikeCJ

Mike:

 Thanks for the reply and I am aware of the "Do No Harm" oath. I was asking if there were any specific regulations since at our facility everything that is brought up as an idea or suggestion must be backed by facts and regulations. I am also aware that at 19.5% oxygen decifient atmosphere, there is another chemical or element at concentrations at about 20,000ppm which means that more than likely at 19.5% O2 your most likely in an IDLH atmosphere and I would not allow anyone to be exposed to anywhere near those levels. Our Halon System would overwhelm the atmosphere in about 30 seconds and make the oxygen levels well below 19.5%. I have found some codes and regulations through OSHA and NFPA but nothing that specifically states how long of a delay should be implemented into a Halon 1301 Manual pull station. I have recommended that a 20 second delay be implimented into the Manual Pull Station but I want to gather as many facts as possible before I am surely to be called into a meeting.

 Our Halon System is old and probably one of the first Halon system installed and I want to make sure I can back what I am saying and recommending.

futureCIH,

You've convinced me. I'd give management the same arguments you gave me. I think the delay only needs to be justified based on travel times to the nearest exit plus some safety factor. Beyond that I think you are good to go.

 MikeCJ