The Occupational Safety and Health Administration believes chemical odor breakthrough is no longer an adequate, sufficient indicator for when workers should change chemical cartridges. Therefore, OSHA's 1998 revision to its respiratory protection standard, 29 CFR 1910.134, requires users of chemical cartridge respirators to implement a cartridge change schedule based on "objective information o...

A new acid -base indicator which is less hazardous and inexpensive is proposed. It is capable of d istinguishing between the acids and bases. Titrations were carried out to ensure that the proposed indicator yields quantitative results. The results of titrations were quite satisfactory. The indicator was giving a distinct sustained colour even in the case of weak base and weak acid titrations. ...