HUD Standard Improves Safety In Mobile Homes, Survey Shows
Fire and life safety has improved dramatically in mobile homes built in compliance with a federal standard enacted in 1976. Furthermore, a survey shows that the installation of smoke detectors makes a marked improvement in fire and life safety in mobile homes of both pre-standard and post-standard vintage.
For the pre-standard homes, which account for three quarters of all mobile homes, the overal situation is bad and is growing worse in some areas.
Rising concern over the life safety of nearly 9 million persons living in mobile homes spurred the United States Department of Housing and Urban Development (HUD) to enact the National Manufactured Housing Construction and Safety Standard (NMHCSS) in 1976. The standard sets requirements for mobile home construction and materials to improve safety from fire and other hazards.
A recently completed evaluation commissioned by HUD to update a 1977 -78 study by the United States Fire Administration (USFA) has confirmed that the ’76 safety standard is reducing the casualties and severity of fires in post-standard mobile homes. This study was conducted by TriData Corporation, a new company specializing in fire and safety data systems, founded by Philip S. Schaenman. As former USFA associate administrator in charge of the National Fire Data Center, Schaenman helped direct the early study.
New homes are significantly lower in casualties per 100 fires, with fewer fires spreading beyond the room of origin. Spread has been even more sharply reduced for fires due to heating and cooking, two areas in which the standard has special provisions.
For all homes, regardless of their age, those with detectors are much safer than those without them. The combination of detectors with the improved escape provisions and reduced flame spread features of the standard produce the safest conditions.
However, leading causes remain basically the same as they were two years ago and the total number of fires and dollar loss for mobile homes appear to be rising. Death and injury rates also continue to be significantly higher than those for conventionally built dwellings.
Value of detectors
An obvious area for improvement is increasing the use of smoke detectors. One way to encourage their installation is through a public education program targeted at the mobile home populace. With a death rate six .times higher for unprotected homes than for those with detectors the importance of these devices for fire safety cannot be overemphasized.
A comprehensive prevention program could also help decrease fire incidence in the first place. With participation by HUD, the fire service, the mobile home industry and various user associations, great potential exists for creating a highly visible, successful public education fire safety effort.
To improve fire safety for future mobile homes, the TriData study recommends further strengthening the standard by supporting expanded use of new fire protection technology. For example, low-cost, quick-reaction sprinklers proved to be extremely effective in a recent full-scale demonstration burn in mobile homes.
Greater statistical base
The TriData study, based primarily on National Fire Incident Reporting System (NFIRS) data, benefits from the increase in the number of states participating in this system. Whereas the 1977-78 study used data from 17 states, the current study uses data from 23 states for 1979 and 25 for 1980.
For 1979, incident reports were available for 4857 mobile home fires, including 209 that caused 295 casualties. For 1980, reports were available for 5320 fires, including 211 that caused 287 casualties. Thus, the data base represents 10,117 mobile home fires—about 20 percent of all the mobile home fires that were reported to fire departments during that period. The year of manufacture of the home was identified for 2442 of the fires. Of these, 410 occurred in homes built in 1976 or later.
The USFA provided additional information on national estimates of the fire problem from a variety of sources, including the National Fire Protection Association, the National Center for Health Statistics, and NFIRS.
In the four post-standard years, 1977-1980, mobile home fires killed over 2000 people, injured over 3000, and caused over $400 million in direct property loss. There were 100,000 mobile home fires reported to fire departments in this period. The number of fires and dollar loss is trending higher, but the number of deaths and injuries is trending lower (see figure 1). An estimated 25,300 mobile home fires were reported to fire departments in 1979, and 27,100 in 1980. The total number of fires may be 5 to 10 times that amount if the ratio of unreported fires is similar to that for other single-family dwellings.
From 1977 to 1980, the number of deaths from mobile home fires decreased by one third to an estimated 413. The death rate per 100 fires decreased even more sharply, by about 40 percent. These reductions are probably due at least in part to effects of the safety standards. Yet, compared to conventionally built one and two-family dwellings, mobile homes continue to have a higher incidence of deaths per 100 fires, even for the newer homes.
The number of injuries also is decreasing, as is the injury rate per 100 fires. But both rates remain significantly higher than for conventional homes.
Dollar loss has risen sharply, to $98.2 million in 1979, and $120.5 million in 1980. Discounting inflation, this rise appears to be tracking the increased number of fires.
Causes of fires
The leading causes of mobile home fires remain heating, electrical distribution, and cooking, in that order. Figure 2 shows the profiles for 19771980. The causes are listed in rank order for 1980. Heating is also the leading cause in conventionally built dwellings, but electrical distribution fires are unusually high in mobile homes.
Why aren’t the cause profiles changing? Probably because the older homes represent three fourths of all mobile homes and the standard does not address fire causes as much as life safety and property damage.
Figure 3 shows a similar comparison for causes of dollar loss. (Data for 1977 dollar loss causes were not available.)
The order of causes is only slightly different for dollar losses than for numbers of fires. Incendiary or suspicious fires, which tend to have higher losses, is third rather than fourth for 1979-1980.
The leading causes of fires that result in deaths and injuries are shown in figures 4 and 5. These cause profiles are significantly different from those for fire incidence and dollar losses. Smoking is the leading cause of deaths, followed by cooking and heating. Cooking is the leading cause of injuries, with heating second and appliance-related (1980) or smoking (1979) fires running third. These patterns are roughly similar to those for conventionally built dwellings.
The NMHCSS appears to be significantly improving life safety in mobile homes from several perspectives. The likelihood of a fire causing a fatality in a pre-standard mobile home is over triple that for a post-standard mobile home, 3.2 deaths per 100 fires for older homes and 1.0 for the newer ones.
The likelihood of a fire causing an injury is 68 percent greater for pre-1976 homes than for the newer homes, 5.7 injuries per 100 fires vs. 3.4.
Detectors reduce casualties
One of the major factors in reducing deaths and injuries is smoke detectors. The standard requires installing them outside each group of bedrooms. We analyzed homes with and without detectors for both the preand post-standard periods. Table 1 shows the results, based on the 1983 fires for which both the year of manufacture of the home and the presence of detectors were known.
For homes without detectors, the deaths per 100 fires (3.7) were six times higher than for homes protected by detectors (0.6)! This ratio greatly exceeds the 2 to 1 ratio found for conventional homes, and highlights the critical importance of early warning.
The table also shows that 1976 and newer homes outperform the old ones with or without detectors. Even those newer homes reported as being without detectors had lower injury and death rates than comparable pre-standard homes.
The life safety improvements of the HUD standard include early detection, easier escape and slower spread of fires. These features also should reduce property loss. Dollar loss per fire was examined to see whether this was the case, but the results were indeterminate. Since newer homes generally are more valuable than older ones, smaller fires in them might cause as much dollar loss as larger fires in older homes.
Flame damage examined
As an alternative, the extent of flame damage was examined, since it describes how large the fire became, independent of dollar loss estimates. Much larger fractions of fires were confined to the room of origin for 1976 and newer homes than for older homes.
However, it is the combination of smoke detectors and other code features that has the most striking effect. Over 70 percent of fires in newer homes with detectors were contained to the room of origin, versus 56 percent for older homes with detectors, and 42 percent for older homes without detectors. Post-1976 homes without detectors outperformed older homes without detectors (48 vs. 42 percent).
A refinement in analyzing the effectiveness of the HUD standard was to consider the degree and avenue of spread for those fires which started inside the home or inside walls or ductwork. The results were that 50 percent of fires that began on the inside did not extend beyond the object or area of origin, compared to only 33 percent in older homes. When only homes with smoke detectors were considered, the percentages confined to the object or area of origin rose to 68 percent in the 1976 and newer homes vs. 48 percent in older homes. In homes without detectors, the results were nearly the same for newer and older homes—32 percent vs. 31 percent, respectively.
These results again suggest that, for homes with detectors, the spread-related fire safety provisions in the HUD standard are particularly effective.
Certain categories of the NMHCSS are directed at cooking fires. Sections 3280.203(a)(4) and 3280.204 specify flame spread and fire resistance of kitchen cabinets, countertops, etc. Sections 3280.203(a)(5), 3280.203(b), and 3280.204 specify flame spread ratings for interior walls near cooking areas.
For the newer homes, less than 15 percent of the cooking fires spread beyond the room of origin, whereas about half the fires in older homes spread beyond the room of origin. Virtually the same results were obtained when the analysis was undertaken for “fires starting in the kitchen” rather than “cooking fires.”
The 167 cooking fires in pre-1976 homes caused 20 injuries, of which three quarters were associated with fires that spread beyond the room of origin. The 41 cooking fires in 1976 and newer homes caused three injuries. The cooking fire injury rate for the older homes is about double that for the newer homes, with the difference largely attributed to fires that spread.
Thus, the standard appears to have helped reduce significantly the likelihood that cooking-related fires will spread and cause injuries. Since cooking fires are one of the leading causes of damage and injuries in mobile homes, these results are particularly important.
Heating is the leading cause of fires and dollar loss in mobile homes. Provisions of the HUD standard aimed specifically at these problems include Sections 3280.203(a)(3) and 3280.203(b), which address flame spread and fireresistance ratings of furnace and water heater spaces. Section 3280.205 addresses carpeting near furnaces and water heaters. Another addresses insulation, and subpart H addresses clearances between heating surfaces and walls and other aspects of heating and cooling systems.
As was the case for cooking fires, heating fires in the newer homes seem to have significantly less spread than in older homes.
Mobile homes continue to experience more severe fires than other dwellings. For 1979-1980, there were 1.8 deaths per 100 fires for mobile homes vs. 0.52 for dwellings. In other words, mobile homes had 3½ times as many deaths per fire as did dwellings.
As mentioned earlier, the deaths per 100 fires has decreased significantly since 1977-1978. The injury rate was 3.9 per 100 fires for mobile homes and 3.1 for dwellings. That is, mobile homes had 1.3 times as many injuries per fire as did dwellings.
Only a small number of deaths (4) and injuries (14) resulted from fires occurring in 410 mobile homes reported as 1976 or newer, and the number of fires, 410, also was relatively small. Therefore, any conclusions must be tentative. Nevertheless, the data indicates that while the HUD standard has helped improve life safety in mobile homes, even the newer homes appear to be much more likely than dwellings to experience casualties when fire occurrs.
The number of deaths per million population living in mobile homes remains about double the rate for dwellings for 1979-1980. The mobile home death rate is about 50 per million. For dwellings, the death rate is about 24 per million for 1979-1980. The various estimates for the number of deaths and the populations are not precise, but the overall ratio seems clearly to be near 2:1.