FDNY A-35 2025/2026 Midterm
Exam (Graded A+)
Air compressors power... - industrial equipment and construction tools
Examples of equipment powered by air compressor are... - pneumatic wrenches, lifts in auto service
stations, paint spray booths
Air compressors enable the - efficient repair of all types of vehicles; and facilitate their safe operation
on public thoroughfares
Permit is required for air compressors that compress air above - 100 PSI
Types of air compressors include - (1) reciprocating
(2) centrifugal
(3) rotary
(4) scroll
How do air compressors work - suck air in from the room into a container. the more air sucked in the
more pressure. pressure can be discharged at a controlled rate.
The 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
(3) steam turbines
How to avoid explosions from air compressors + why would it happen - Flammable gasses can be
built up in places like workshops. These gases are usually heavy and sink to the floor before
, spreading out. To avoid suction into the air compressor which would cause an explosion - the air
compressor must be raised at LEAST 5 feet above ground level.
To meet the height requirement you can place compressor on a shelf or bench OR bolt the
compressor to the top of its standing air reciever.
An air compressor is powered by... - an electric motor. The motor activates a series of drive belts. The
belts then power the moving parts of the unit.
Air is compressed in compression chamber which consists of a - 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 valve automatically closes to avoid air escaping
from cylinder).
Air Reciever - supplies compressed air when needed.
When air pressure reaches a certain level, it forces open a DISCHARGE VALVE (which is spring
loaded). This releases compressed air into the air reciever (aka air tank).
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.
This is why in a multi stage air compressor there is an intercooler between stages of compressor.
Exam (Graded A+)
Air compressors power... - industrial equipment and construction tools
Examples of equipment powered by air compressor are... - pneumatic wrenches, lifts in auto service
stations, paint spray booths
Air compressors enable the - efficient repair of all types of vehicles; and facilitate their safe operation
on public thoroughfares
Permit is required for air compressors that compress air above - 100 PSI
Types of air compressors include - (1) reciprocating
(2) centrifugal
(3) rotary
(4) scroll
How do air compressors work - suck air in from the room into a container. the more air sucked in the
more pressure. pressure can be discharged at a controlled rate.
The 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
(3) steam turbines
How to avoid explosions from air compressors + why would it happen - Flammable gasses can be
built up in places like workshops. These gases are usually heavy and sink to the floor before
, spreading out. To avoid suction into the air compressor which would cause an explosion - the air
compressor must be raised at LEAST 5 feet above ground level.
To meet the height requirement you can place compressor on a shelf or bench OR bolt the
compressor to the top of its standing air reciever.
An air compressor is powered by... - an electric motor. The motor activates a series of drive belts. The
belts then power the moving parts of the unit.
Air is compressed in compression chamber which consists of a - 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 valve automatically closes to avoid air escaping
from cylinder).
Air Reciever - supplies compressed air when needed.
When air pressure reaches a certain level, it forces open a DISCHARGE VALVE (which is spring
loaded). This releases compressed air into the air reciever (aka air tank).
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.
This is why in a multi stage air compressor there is an intercooler between stages of compressor.
