Interscan Respectfully Offers A Few Suggestions To The Agency

Interscan Corporation, a leading manufacturer of gas detection instrumentation, has often noted that toxic gas analyzers are only as good as their calibration. While no one in the industry would dispute this contention, official support and guidance from OSHA are sorely lacking.

According to Grant McClure, Interscan's manager of special projects, "OSHA goes into extravagant detail on many safety-related matters, but offers little on gas detector calibration beyond following the manufacturer's recommendations. Are they trying to be scrupulously evenhanded, or are they afraid of entering the fray, so to speak?"

A few years ago, OSHA did post a document—a so-called Safety and Health Information Bulletin—entitled "Calibrating and Testing Direct-Reading Portable Gas Monitors." Only, the agency did not write it. It was provided (indirectly) by the manufacturers, from the International Safety Equipment Association (ISEA). Its nearly 1800 words provide a decent, if limited, introduction to the subject.

However, the Bulletin assiduously ignores the fact that in most cases, obtaining a suitable gas calibration standard can be difficult, or even impossible. Neither ISEA nor OSHA seem to acknowledge that there is more to gas detection than confined entry, combustible gases, carbon monoxide, hydrogen sulfide, and oxygen deficiency.

Thus, Interscan has posted an article to its Knowledge Base, in which the OSHA bulletin is presented, along with helpful commentary.

Among other things, the commentary suggests that OSHA—and everyone else—jettison the use of the description "direct-reading," since it is at least four decades out of date. It also stresses being more careful with such terms as "drift," "accuracy," and "calibration," itself. And, the commentary notes that permeation devices are not even mentioned, nor is the general lack of calibration standards for many compounds.

Robert Ramos, Interscan sensor technician, asks, "How can OSHA establish permissible exposure limits (PELs) for so many gases, yet remain silent on all but the simplest calibration solutions?"

Rose Stransky, Interscan sales engineer states, "We get questions on calibration every single day, and when we answer them, we often hear that no other gas detection company seems to care about this issue."