Forcible Entry Demonstrations
Page 5
Air-blast Resistant Window Systems
been shown to be a major contributor to injuries in such events. In the bombing of the
Alfred P. Murrah Building in Oklahoma City, for instance, 40% of the survivors within
the Murrah Building cited glass as contributing to their injuries. Within nearby buildings,
laceration estimates ranged from 25% to 30% [1].
Not just the targeted building's windows are affected by the explosive forces; past
incidents have shown that glass breakage may extend for miles in large external
explosions. Also, for explosions within downtown city areas full of glass-clad high-rise
buildings, falling glass poses a major hazard to passersby and prolongs post-incident
rescue and clean- up efforts by leaving tons of glass debris on the street.
Explosion-related injuries are classified as primary, secondary, and tertiary. Glass
breakage contributes to all three of these injury groups. The high pressure of the air-blast
that enters through broken windows may cause eardrum damage and lung collapse (or
"primary" injuries). As the air-blast damages the building components in its path, debris
becomes missiles which cause impact injuries (or "secondary" injuries). Airborne glass
fragments typically cause penetration- or laceration-type injuries. Larger (non- glass)
fragments may cause non-penetrating, or blunt trauma injuries. Finally, the air-blast
pressures cause occupants to be bodily thrown against objects or to fall ("tertiary"
injuries). These effects are summarized in Table 1.
Table 1. Explosion-Related Injury Types
Injury Classification Injury Type
Cause
Primary
Eardrum rupture, lung collapse
Air-blast pressure levels
Secondary
Lacerations and blunt trauma injuries
Missile impact
Tertiary
Being thrown or falling due to the force of the
Air-blast pressure impact
explosion
3. Standard Forcible Entry Procedures
Although every fire department has unique standard operating procedures, the following
steps outline fundamental elements which all departments' procedures incorporate in
some manner:
Access into burning structure for rescue or fire attack
o From the exterior
o Generally made on the first several floor levels
Venting the fire
o From exterior or interior, depending on the department's protocols and the
specific situation
o Any floor level
Egress from the building, sometimes under emergency conditions
o From the interior
o From any floor level
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