Whether at trade shows or in person, a subject that’s often raised by members is metering. How and why do we do it? What do the numbers mean? What do I do with the numbers?
Members seemingly are overwhelmed. Even members who have been doing metering for a long time wonder, “Why is it so difficult to understand?” Newer members press for details, because they frantically are searching for anything to help them to operate more efficiently.
The process of metering is vitally important for all levels of hazmat, because it does what we humans can’t: detect what’s in the air that potentially can harm us. Our noses are rather good at some things: smelling hazmat, not so much. Further, metering lets us know the amount of contaminant that’s in the air, so we can make tactical decisions, such as where to run, what to wear and how quickly to move.
Metering has served us faithfully for many years, but one of the major initial problems in this disconnect from our senses is turning over the controls to something that only gives us a number or a sound. What was internalized now is externalized, and we use more knowledge and understanding than gut feelings to make a decision.
Why we monitor
Meters establish a few important parameters for all members to operate safely. For instance, they establish zones for both responders and the public. In big terms, we use the zones “cold,” “warm” and “hot” based on meter readings. However, even “hot” can be broken into levels, including permissible exposure limits (PEL)—or SCBA on—and immediately dangerous to life and health (IDLH)—or change your PPE and mitigation-area boundaries.
Meters also can be used to locate a leak to a specific area and to determine whether an atmosphere is flammable, toxic or corrosive. Each of those might require a completely different choice of PPE, and, from where we sit, that’s very important information.
Finally, meters are used to simply find out whether actions that are taken are having an effect on the operation. “We closed a valve. Did it work? Check the meter.”