Bronx five-alarm fire driven by wind destroys a roof and takes the risers with it

NEW YORK, N.Y.

A five-alarm fire driven by heavy winds destroyed the top-floor apartments of a multi-family building on Wallace Avenue in the Bronx and forced more than 60 families into temporary Red Cross shelters, according to NBC New York.

Emergency structural assessments now indicate that the destruction of the roofing system has compromised the building's internal risers, and a round-the-clock physical security perimeter is in place to protect the property against looting and against the risk of structural collapse.

Wind changes the fire and the response

A top-floor fire in a high-wind condition behaves like an exterior fire that happens to be inside a building. Wind drives the flame front across the roof assembly, pushes it through ventilation openings and prevents vertical ventilation from working the way it is intended, because the products of combustion are being pushed back down through the structure rather than allowed to leave it. Crews end up chasing fire through cockloft spaces and roof layers while the building below fills with smoke.

The consequence is a roof that has lost its sheathing over a large area. That is a structural problem above and a water problem below, and it is the reason the assessments reached the risers.

Risers are the building's firefighting water, and they fail quietly

A standpipe riser is a dry or wet pipe that runs vertically through a building so that crews can connect to it on an upper floor instead of stretching hose up the stairs. It is part of the fire protection system, and it is out of service when the roof structure that supports its top section is gone, when the pipe has been distorted by heat, or when water entered and froze in a section that was not drained.

A building without a functioning standpipe is a building the fire department cannot defend at height. That condition, combined with the absence of detection and partial sprinkler protection, is precisely what a fire watch exists to cover. NFPA 25 requires a watch when suppression is out of service beyond the allowable interval, and the fire department and the building official can require one for the wider loss of protection.

The perimeter is two jobs at once

The first is collapse. A building whose roof has been consumed and whose upper walls have lost their bracing has a collapse zone that belongs to the building official, and the post enforces it for everyone: residents, press, contractors and the people who want to look. The second is theft. An evacuated building is a building full of unclaimed property with doors that no longer lock and lighting that no longer works, and the record shows that unguarded fire buildings are entered quickly.

Both jobs require a post that controls the approaches, logs every entry and exit, and works the night hours when the block is empty. Coverage is sustained until the Department of Buildings releases the structure and the property secures it.

The USPA position

USPA Nationwide Security staffs fire watch and perimeter details in the Bronx across New York City, with uniformed officers assigned to collapse-zone enforcement, access control and documented rounds. Buildings with a compromised standpipe or suppression system can open coverage through the emergency fire watch desk. For properties in New York City, fire watch coverage in New York City is posted from officers already working the market, which is what keeps a same-day start possible.

Related reporting from the newsroom: 10-Year-Old Boy Killed in Patterson Houses Fire; FDNY Says E-Bike Battery Caused the Blaze.