Recently I've been working on some confined space curriculum so I thought I would share some of the issues that confined spaces present to firefighters. Reading through various articles and reports you will see that there is a common hazard that we face when dealing with confined spaces. That hazard is an immediately dangerous to life and health (IDLH) atmosphere. A majority of the time when there is an IDLH atmosphere there’s no visual cues to let you know that there is something wrong. Most of gases that we face in an IDLH atmosphere are colorless and odor less. Because most of the gases are colorless and odorless they require us to have a good gas monitor to detect the various gases that we have the potential to face. Also we need to be able to interpret the readings from that gas monitor and have an understanding of what they mean. Too often I see people not operating the gas monitor properly. The biggest mistake that I see people making is they ends up putting the monitor in too quickly or just dropping the monitor in on a rope. Every gas monitor is different but the thing that is the same is it takes the monitor a few seconds to read the sample. So going too fast will not allow the monitor the appropriate amount of time to read the sample. You need to give the monitor an appropriate amount of time to read the sample or you will not get a good reading. Each manufacture is different so consult you manufacturers guide to know how long it takes for the monitor to read the sample. Dropping the monitor into the space on the rope should be the last resort. Gases can stratify depending on their vapor density in a confined space. Stratification gives you different readings at different spots in the space. So you could have a low oxygen reading at the bottom but by the time you bring the monitor up it could be reading normal. Your monitor should give you your high and low reading and you should be able to see what you highs and lows are. You have to be familiar with your gas monitor to be able to read the hi and low readings. The biggest issue with dropping the monitor in the hole is you don’t know where those readings are from. Hazardous atmospheres are the biggest issue when dealing with confined spaces. Having a good knowledge of what hazards are present, how to how to detect any unknown hazards and how to mitigate the atmospheric hazards are vital when dealing with confined space incidents. Almost every community the country has a confined space. Below is a summary report from the NFPA concerning fatalities from confined space incidents. Also a NIOSH report from a line of duty death dealing with a confined space. Then there's a near miss report from an confined space incident in Florida.
