FDNY A-35 2025 FINAL EXAM
(Graded A+)
Air compressors power... - (1) industrial equipment and (2) construction tools
Examples of equipment powered by air compressor - pneumatic wrenches, lifts in auto service
stations, paint spray booths
Air compressors enable... - (1) efficient repair of all types of vehicles; and (2) facilitate their safe
operation on public thoroughfares
Permit is required for air compressor - that compresses air above 100 PSI
Types of air compressors - (1) reciprocating;
(2) centrifugal;
(3) solar; and
(4) rotary
*Difference is the way in which they compress air
How do air compressors work - take the air in a room and force it into a container UNDER PRESSURE.
The more air forced into the container, the greater the pressure. Compressed air can be discharged
from the container at a controlled rate.
Most common air compressor - Reciprocating
Air compressors are sometimes called - air pumps
Air compressors can be powered by: - (1) electric motors;
(2) internal combustion engines; or
(3) steam turbines
, Explosions & air compressors - If there is a build up of flammable gases (ex: in service stations and
workshops), those gases are heavier than air and fall to the floor before spreading outward. These
gases are easily ignited by sparks and high temperatures--which INCLUDES the heat generated by an
air compressor.
To avoid explosions w/ air compressors - Raise air compressor at LEAST 5 feet above ground level so
that no flammable gases are drawn into the compressor. To meet the height requirement you can
place compressor on a shelf or bench OR the air receiver tank may be turned and stood on end w/
the air compressor bolted to the top of the tank.
Power to air compressor - entire unit is driven by an electric motor. Motor activates a series of drive
belts. Belts power the moving parts of the unit--like w/ power steering and alternator in automobile
Compression Chamber operation - Air is compressed in compression chamber which consists of a
PISTON inside a CYLINDER. Piston moves up and down.
When piston moves down -->draws air into cylinder, through INTAKE VALVE (valve automatically
opens when piston moves down).
When piston moves up-->air is compressed (intake vale automatically closes to avoid air escaping
from cylinder).
Air Reciever Operation - When air pressure reaches a certain level, it forces open a DISCHARGE VALVE
(which is spring loaded). This releases compressed air into air reciever (aka air tank), which is what
supplies compressed air when needed.
Single Stage Air Compressor - with one cylinder and one piston
Multi Stage Air Compressor - with more than one piston and cylinder.
Each cylinder will increase the pressure of the air by taking air from the discharge side of the
previous cylinder and increasing the pressure to a new level. Once it reaches the last level, the
pressurized air is discharged into the reciever.
As air is compressed it becomes - heated.
(Graded A+)
Air compressors power... - (1) industrial equipment and (2) construction tools
Examples of equipment powered by air compressor - pneumatic wrenches, lifts in auto service
stations, paint spray booths
Air compressors enable... - (1) efficient repair of all types of vehicles; and (2) facilitate their safe
operation on public thoroughfares
Permit is required for air compressor - that compresses air above 100 PSI
Types of air compressors - (1) reciprocating;
(2) centrifugal;
(3) solar; and
(4) rotary
*Difference is the way in which they compress air
How do air compressors work - take the air in a room and force it into a container UNDER PRESSURE.
The more air forced into the container, the greater the pressure. Compressed air can be discharged
from the container at a controlled rate.
Most common air compressor - Reciprocating
Air compressors are sometimes called - air pumps
Air compressors can be powered by: - (1) electric motors;
(2) internal combustion engines; or
(3) steam turbines
, Explosions & air compressors - If there is a build up of flammable gases (ex: in service stations and
workshops), those gases are heavier than air and fall to the floor before spreading outward. These
gases are easily ignited by sparks and high temperatures--which INCLUDES the heat generated by an
air compressor.
To avoid explosions w/ air compressors - Raise air compressor at LEAST 5 feet above ground level so
that no flammable gases are drawn into the compressor. To meet the height requirement you can
place compressor on a shelf or bench OR the air receiver tank may be turned and stood on end w/
the air compressor bolted to the top of the tank.
Power to air compressor - entire unit is driven by an electric motor. Motor activates a series of drive
belts. Belts power the moving parts of the unit--like w/ power steering and alternator in automobile
Compression Chamber operation - Air is compressed in compression chamber which consists of a
PISTON inside a CYLINDER. Piston moves up and down.
When piston moves down -->draws air into cylinder, through INTAKE VALVE (valve automatically
opens when piston moves down).
When piston moves up-->air is compressed (intake vale automatically closes to avoid air escaping
from cylinder).
Air Reciever Operation - When air pressure reaches a certain level, it forces open a DISCHARGE VALVE
(which is spring loaded). This releases compressed air into air reciever (aka air tank), which is what
supplies compressed air when needed.
Single Stage Air Compressor - with one cylinder and one piston
Multi Stage Air Compressor - with more than one piston and cylinder.
Each cylinder will increase the pressure of the air by taking air from the discharge side of the
previous cylinder and increasing the pressure to a new level. Once it reaches the last level, the
pressurized air is discharged into the reciever.
As air is compressed it becomes - heated.
