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January 2008 

Missing Ceiling Tiles 

Properly installed ceiling systems allow 

smoke detectors, heat detectors, and fire 

sprinklers to operate correctly in the event 

of a fire. They also provide a barrier to 

the spread of smoke and fire. Breaking,

displacing, or removing ceiling tiles enables 

hot gases and smoke from a fire to rise and 

accumulate above detectors and sprinklers. 

Doing so delays their activation, enabling 

fires to rapidly grow larger before an alarm

and response occur. 

Ceiling tile breakage, displacement, 

or removal often occurs as a result of 

mechanical system repair or maintenance. 

Because fires are unpredictable, intact tiles 

must be returned to their intended positions 

as soon as possible following such repairs.

Office occupants also often move aside or 

remove ceiling tiles, typically to improve 

personal comfort by altering local air 

currents. The danger this creates impacts 

not only the person who moves the tile, 

but also endangers all building occupants. 

Moreover,olderceilingtilesmayalsocontain 

asbestos, so disturbing them can cause yet 

another health hazard (See the Office of 

Compliance’s “Asbestos: Do Not Disturb” 

Fast Facts). 

Thesmokeandhotgasesfromafiredecrease 

in concentration as height and horizontal 

distance from the center of the fire increase. 

Once the smoke and hot gases reach the

ceiling, they travel horizontally, creating a 

“ceiling jet.” This ceiling jet is what typically

triggers smoke alarms, heat detectors, and 

sprinkler systems. 

Removalofceilingtilescanenablesmokeand 

hot gases to rise above the remaining ceiling 

system, circumventing the fire protection 

systems located at or slightly below the level 

of the ceiling. If a fire starts in a room with 

a missing ceiling tile, the ceiling jet can

travel to the hole created by the missing tile, 

and will rise into the space above the drop

ceiling, which typically lacks monitoring 

devices. This may delay smoke detectors 

from receiving the smoke concentration 

needed to actuate them and to send an alarm 

signal. Most of the heat may also rise into

the space above the ceiling, bypassing heat

detectors and sprinklers completely. This 

www.compliance.gov


Figure 2: Removal of ceiling tiles may damage 

wiring to detectors mounted below them. 

renders them ineffective until the smoke and 

heat fill the space above, greatly lengthening 

the time ittakesforthemtoactuate.Because 

fires can double in size each minute, this 

delay enables a fire to grow much larger and

become more difficult to extinguish. 

Missing ceiling tiles are not just a risk 

to those in the area where the tiles were 

removed. Space above a drop ceiling system

often provides a route for air to be drawn 

back to a conditioner ductwork and fan that 

re-circulates the air. Therefore, smoke that

enters this space is often spread to other areas

in the building, exposing other occupants to 

smoke and toxic gases. 

Minimizing the number of unnecessary 

ceiling openings will make a building 

safer for all occupants. Employees should 

report any unnecessary ceiling openings to 

appropriate maintenance authorities. 

Figure 1: Missing and damaged ceiling tiles 
fast stats 

•	OSHA requires that safeguards designed to protect employees during an emergency—including displaced

ceiling tiles—must be in proper working order at all times (29 CFR §1910.37(a)(4)).

•	The NFPA requires that smoke barriers be provided to subdivide building spaces for the purpose of restricting

the movement of smoke (NFPA 101 8.5.1).

•	OSHA requires employee alarm systems to provide warning necessary for reaction time for safe escape

of employees from the workplace or the immediate work area, or both. Missing ceiling tiles would delay

the activation of detection and alarm systems, thereby decreasing the time for safe evacuation (29 CFR

§1910.165(b)(1)).

•	The Office of Compliance found nearly 200 locations where incomplete ceilings impacted the operation of fire

protection systems during the biennial safety and heath inspections conducted during the 109th Congress.

Definitions 

•	Smoke Barrier: A continuous membrane, or a membrane with discontinuities created by protected openings,

where such membrane is designed and constructed to restrict the movement of smoke.

•	Ceiling Jet: A stream of risen smoke and hot gases that travel horizontally along the bottom of an intact ceiling.

If you spot a safety hazard in your legislative branch 

workplace, contact the Office of Compliance to report it: 

Room LA 200, John Adams Building 

110 Second Street, SE 

Washington, DC 20540 

t/ 202-724-9250; tdd/ 202-426-1912; f/ 202-426-1913 

Recorded Information Line/ 202-724-9260 

www.compliance.gov 

The Office of Compliance advances safety, health,

and workplace rights in the U.S. Congress and the 

Legislative Branch. Established as an independent

agency by the Congressional Accountability Act of 

1995, the Office educates employees and employing 

offices about their rights and responsibilities under the 

Act, provides an impartial dispute resolution process,

and investigates and remedies violations of the Act. 

Peter Ames Eveleth 

General Counsel 

Rachel Berg Scherer 

Editor 

This information does not constitute advice or an official ruling of the Office of Compliance or the Board of Directors and is intended for educational 

purposes only. For further information, please refer to the Congressional Accountability Act (2 U.S.C 1301 et seq.) and the regulations issued by the 

Board, or you may contact the Office of Compliance.