Are simple alarm devices considered to be the “direct reading instruments” referenced in paragraph (c)(5)?
No, simple “alarm only” devices which do not provide readings, are not considered acceptable direct reading instruments, for either initial (pre-entry) or periodic (assurance) testing of a “(c)(5)” space since they do not provide enough information relative to the established acceptable entry conditions which is essential to the entrants knowledge. Combination units which have a meter or display which reflect the actual concentrations and a preset alarm feature would be acceptable and possibly desirable because they provide “real time” information on actual concentrations as well as the benefit of automatic (unattended) alarming at a predetermined value.
