The Overhaul of Z21.11.2
Z21.11.2 may never have been in danger of being scrapped, but a major revision was inevitable. Space heaters were getting a bad name, and worse yet, the federal government, for the first time ever, was considering regulating a gas appliance. The results were significant. Between 1960 and 1980 the committee added requirements for an automatic ignition system, a pilot regulator, lower surface temperatures, and improved shielding. The average retail price of the appliances more than tripled as a result, from around $50 to approximately $180. How beneficial were these requirements? Opinions vary, and the data are inconclusive.
Surface temperatures have come down slightly over the years, reducing the burn hazard to some extent. Organizations such as Consumers Union argue for further reductions. This would not prevent accidents, of course, but it would provide a longer response time before a burn injury becomes serious. How that would translate into the real world of product injuries is impossible to say. There are no good estimates of the number of injuries involving surface burns, let alone how changes in surface temperature might affect them. Significantly lower surface temperatures probably cannot be obtained, however, without substantial changes in heater design. The cost and feasibility of this task cannot be estimated without research and development work. If, as manufacturers argue, surface temperatures cannot be reduced without dramatic changes in design, then it is likely that the cost would not justify the fractional change in response time to accidents. Similar uncertainty confounds any analysis of the other performance tests in Z21.11.2. The clothing ignition test, long criticized for using twenty-pound paper, was revised to incorporate the use of terry cloth. This makes the test more realistic, but the real-world significance of the revised test method is impossible to ascertain given existing data. And without access to con-
fidential certification records, it is impossible to determine whether the new test resulted in actual product changes.
Perhaps the most dramatic result of these changes was elimination of a model of small bathroom heaters known to be connected with many injuries. This "drop-out ban," as a trade association representative dubbed it, apparently did not improve the image of the unvented heater enough to forestall government intervention. But the industry claims that the overhaul of Z21.11.2 improved the safety of the product sufficiently to eliminate almost all carbon monoxide deaths. The CPSC disputes this claim.