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We recently received a question through the “Ask the Experts” section of the website about fixed gas detection. We think that it’s worthy of a blog posting and a deeper dive. This is what the individual wanted to know:

Do you have guidance on the use of personal gas detection versus fixed gas detection devices? For example, is using portable gas detection monitors good enough or are there scenarios where fixed heads are required (e.g. at vent points, etc.).Personal gas detectors stay connected to workers, ensuring they have continuous gas detection coverage in the field.

This is an excellent question, and I’ll start by saying there really is no right answer here. I am of the opinion that it is never right to forego using a personal monitor because you have a fixed detector in place in an area. Personal portable monitors and fixed gas monitors are typically used for different purposes. Fixed monitors are generally put in places primarily to protect the facility, to detect catastrophic leaks or to be an early warning of gases leaking from a system. Personal monitors are designed to protect personnel who may be working in a given area. Fixed or portable, all of the detectors are point detectors in that they will only detect gas in direct contact with the sensors. People are portable, meaning that they move in and about any given area. With that said, there is no way a fixed detector, which will only detect gas that diffuses into it, can completely cover the leak potential in any given area and the likelihood that a leaking gas and a worker both migrate to an area that is uncovered by a fixed detector is extremely high. Therefore, I don’t ever believe that a fixed detector can be a hands-down choice over a portable personal monitor.

The second issue is that fixed gas detection systems, I’m sorry to say, generally lack the routine and preventive maintenance that should be performed on them. I have seen far too many instances of unmaintained fixed gas detection systems that simply did not work and no one was the wiser. Unfortunately, there really is no way to know that a fixed gas detection system is working properly before you send workers into a given area. Portable or fixed, it doesn’t matter. The only way that you can be certain that a gas detector will actually detect gas is to test it with gas.

Don’t get me wrong. I am not saying that fixed gas detection systems don’t play a big role in safety. Fixed gas detection systems are often required to protect facilities by the insurance companies who are underwriting them and even by some standard electric codes. By protecting the facility, they are also protecting the lives of the people working in the facility. A fixed gas detection system can provide an early warning of hazardous gas before a worker steps foot in a given area. But if I am betting my life on a gas detector doing its job and properly protecting my life, I am going with a personal portable monitor every time.