Construction Types

Question 1

Type 1A

Answer 1

Concrete construction. Fire Resistive Non-combustible (Commonly found in high-rise buildings and Group I occupancies).
3 Hr. Exterior Walls*
3 Hr. Structural Frame
2 Hr. Floor/Ceiling Assembly
1 ½ Hr. Roof Protection

Question 2

Type 1B

Answer 2

Protected Steel construction with insulation. Fire Resistive Non-Combustible (Commonly found in mid-rise office & Group R buildings).
2 Hr. Exterior Walls*
2 Hr. Structural Frame
2 Hr. Ceiling/Floor Separation
1 Hr. Ceiling/Roof Assembly

Question 3

Type 2A

Answer 3

Concrete or masonry walls with unprotect roof joist or beam.
Protected Non-Combustible (Commonly found in newer school buildings).
1 Hr. Exterior Walls
1 Hr. Structural Frame
1 Hr. Floor/Ceiling/Roof Protection

Question 4

Type 2B

Answer 4

Unprotected Non-Combustible (Most common type of non-combustible construction used in
commercial buildings).
Building constructed of non-combustible materials but these materials have no fire resistance.

Question 5

Type 3A

Answer 5

Protected Combustible (Also known as “ordinary” construction with brick or block walls and a
wooden roof or floor assembly which is 1 hour fire protected).
2 Hr. Exterior Walls*
1 Hr. Structural Frame
1 Hr. Floor/Ceiling/Roof Protection

Question 6

Type 3B

Answer 6

Unprotected Combustible (Also known as “ordinary” construction; has brick or block walls with a
wooden roof or floor assembly which is not protected against fire. These buildings are frequently found in
“warehouse” districts of older cities.)
2 Hr. Exterior Walls*
No fire resistance for structural frame, floors, ceilings, or roofs.

Question 7

Type 4A

Answer 7

Heavy Timber (also known as “mill” construction; to qualify all wooden members must have a
minimum nominal dimension of 8 inches.)
3 Hr. Exterior Walls*
3 HR. Interior Walls
3 Hr. Structural Frame
2 HR. Floor Construction and secondary structural members
1.5 HR. Roof construction

Question 8

Type 4B

Answer 8

Heavy Timber (also known as “mill” construction; to qualify all wooden members must have a
minimum nominal dimension of 8 inches.)
2 Hr. Exterior Walls*
2 HR. Interior Walls
2 Hr. Structural Frame
2 HR. Floor Construction and secondary structural members
1 HR. Roof construction

Question 9

Type 4C

Answer 9

Heavy Timber (also known as “mill” construction; to qualify all wooden members must have a
minimum nominal dimension of 8 inches.)
Heavy timber interior walls permitted to be unprotected
2 Hr. Exterior Walls*
2 HR. Interior Walls
2 Hr. Structural Frame
2 HR. Floor Construction and secondary structural members
1 HR. Roof construction

Question 10

Type 4-HT

Answer 10

Heavy timber. Exterior walls are of non combustible materials and the interior building elements are of solid wood, laminated heavy timber or structural composite lumber (SCL). Interior walls or partitions not less than 1 hour fire protection rating are permitted.

Question 11

Type 5A

Answer 11

Protected Wood Frame (Commonly used in the construction of newer apartment buildings; there is
no exposed wood visible.)
1 Hr. Exterior Walls
1 Hr. Structural Frame
1 Hr. Floor/Ceiling/Roo

Question 12

Type 5B

Answer 12

Unprotected Wood Frame (Examples of Type V-N construction are single family homes and
garages. They often have exposed wood so there is no fire resistance.)