Building damage

A slow response to a smoldering mix of chemicals at the Napp Technologies plant in Lodi, NJ is blamed for an April 21,1995 explosion and fire that killed four workers and injured dozens of others. The blast destroyed more than 70% of the plant, which made pharmaceutical and cosmetic iiuerniediate products, and employed 110 workers. The explosion wrecked several stores housed in (he Napp building, damaged nearby buildings, and forced evacuation of 400 residents for about 13 hours. Chemicals leaked into a nearby river, killing hundreds of fish. 

Eaglcman, J. R. Muirhead, V. U. and Willems, N. (1975). Thunderstorms, Tornadoes, and Building Damage. Toronto Lexington Books. 

Minor Building performs function. Building is reusable following an explosion. Only minor repairs needed. Very little risk to occupants because of building damage. Zero to 10 days of downtime. 

Moderate Building performs function. Building is not reusable following an explosion. Major repairs needed that equal or exceed replacement cost. Risk of some injury to some occupants caused by building damage. Ten to 90 days of downtime. 

Major Building severely damaged. High risk of severe injury to occupants caused by building damage. Downtime in excess of 90 days. 

Determination of Occupant Vulnerabilities as a Function of Building Damage... 

B.2. Assessment of Building Damage and Probability of serious Injuries/Fatalities... 

VibratioiVliquid Pumps, valves, instru- Other containment Building damage... 

From the calculated building damage versus response relationship and the empirical probability of serious injury or fatality versus damage relationship discussed above, the relationship between explosion overpressure (or other effects) and probability of serious injury or fatality may be constructed in a manner that accounts for the detailed structural characteristics of plant buildings. The steps involved are similar to risk screening (Chapter 4), with the addition of detailed quantitative structural evaluation of plant buildings and detailed quantitative frequency assessment as described in the next section. 

Determination of occupant vulnerabilities as a function of building damage... 

Correlation of Building Damage and Explosion Response of Structural Steel Elements... 

Figure 17. Impulse Versus Pressure Diagram for Constant Levels of Building Damage. (Reprinted with permission from ref. 15. Copyright 1983 Elsevier Science.)...

Table 24 Comparison between cases of building damage, morgue and disinfestation chamber...

Table 3.5 summarizes the effects of explosion overpressure on structures. With respect to human casualties, heavy building damage usually is equated to a fatal effect, as the people inside the buildings probably would be crushed. People outside of buildings or structures are susceptible to direct blast injury (blast overpressure) and indirect blast injury (missiles or whole body translation). 

Leave or avoid buildings damaged or threatened by the explosion. 

No real damage to buildings. Damage to unanchored mobile homes. Some damage to poorly constructed signs. Also, some coastal flooding and minor pier damage. 

The sound level experienced at a distance from an explosion can be heavily depended on transient atmospheric conditions (e.g. temperature inversions, wind shear, and even gusts of wind). The low frequency air pressure from a blast can cause vibration in buildings, in addition to its startle effect. Such vibration can give rise to concern about possible building damage at relatively low over-pressure levels. The subject has been investigated in depth by the United States Bureau of Mines, whose conclusions are summarised in [33.11]. 

Table 4. Situation of surface maximum deformation and buildings damage.

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