Annex C(Clauses 3.3.2 and 3.3.3) Available Data Regarding Fire Resistance Rating of Various Building Components

NBC 2016 (SP 7:2016) Volume 1

2016 · PDF page 327

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Table 10Masonry Walls: Solid (Required to Resist Fire from One Side at a Time) (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm), Excluding any Finish for a Fire Resistance (min) of
		Load Bearing					Non-load Bearing
		60(3)	90(4)	120(5)	180(6)	240(7)	60(8)	90(9)	120(10)	180(11)	240(12)
i)	Reinforced cement concrete $^{1)}$	120(25) $^{2)}$	140(25) $^{2)}$	160(25) $^{2)}$	200(25) $^{2)}$	240(25) $^{2)}$	—	—	—	—	—
ii)	Unreinforced cement concrete	150	175	—	—	—	—	—	—	—	—
iii)	No-fines concrete with:a) 13 mm cement/sand or gypsum/sandb) 13 mm light weight aggregate gypsum plaster	—	—	—	—	—	150	150	150	150	150
iii)		—	—	—	—	—	150	150	150	150	150
iv)	Bricks of clay:a) Without finishb) With 13 mm lightweight aggregate gypsum plaster	9090	10090	10090	170100	170100	7575	9090	10090	17090	170100
v)	Bricks of sand lime:a) Without finishb) With 13 mm lightweight aggregate gypsum plaster	9090	10090	10090	190100	190100	7575	9090	10090	17090	170100
vi)	Blocks of concrete:a) Without finishb) With 13 mm lightweight aggregate gypsum plasterc) With 13 mm cement/sand or gypsum/sand	9090	10090	10090	—100	—100	7575	9075	10075	14090	150100
vi)		—	—	—	—	—	75	90	90	100	140
vii)	Blocks of lightweight concrete:a) Without finishb) With 13 mm lightweight aggregate gypsum plasterc) With 13 mm cement/sand or gypsum/sand	9090	10090	10090	140100	150100	7550	7563	7575	12575	14075
vii)		—	—	—	—	—	75	75	75	90	100
viii)	Blocks of aerated concrete:a) Without finishb) With 13 mm lightweight aggregate gypsum plaster	9090	10090	100100	140100	180150	50—	63—	63—	75—	100—

Walls containing at least 1 percent of vertical reinforcement.

$^{2)}$ Minimum thickness of actual cover to reinforcement.

Table 11Masonry Walls: Hollow (Required to Resist Fire from One Side at a Time) (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm), Excluding any Finish for a Fire Resistance (Min) of
		Load Bearing					Non-load Bearing
		60(3)	90(4)	120(5)	180(6)	240(7)	30(8)	60(9)	90(10)	120(11)	180(12)	240(13)
i)	Bricks of clay:
	a) Without finish	170	170	170	200	200	75	75	90	100	170	170
	b) With 13 mm lightweight aggregate gypsum plaster	100	100	170	170	170	75	75	90	90	90	100
ii)	Blocks of concrete:
	a) Without finish	—	—	—	—	—	90	125	125	140	140	150
	b) With 13 mm cement/sand or gypsum/sand	—	—	—	—	—	90	125	125	140	140	140
	c) With 13 mm lightweight aggregate gypsum plaster	190	200	200	—	—	75	90	90	100	125	125
iii)	Blocks of lightweight concrete:
	a) Without finish	100	100	100	—	—	75	90	90	100	140	150
	b) With 13 mm cement/sand or gypsum/sand	—	—	—	—	—	75	75	75	100	140	140
	c) With 13 mm lightweight aggregate gypsum plaster	—	—	—	—	—	63	63	63	75	90	100

Table 12Framed Construction, Load Bearing (Required to Resist Fire from One Side at a Time) (Clause C-1)

Sl No.	Nature of Construction and Materials/Timber Studs at Centres not Exceeding 600 mm, Faced on Each Side with	Minimum Thickness (mm) of Protection for a Fire Resistance of 60 min
(1)	(2)	(3)
i)	Plasterboard layers with joints staggered, joints in outer layer taped and filled - Total thickness for each face	25
ii)	One layer of 12.7 mm plasterboard with a finish of lightweight aggregate gypsum plaster	13
iii)	Metal lath and plaster, thickness of plaster: a) Sanded gypsum plaster (metal lathing grade) b) Lightweight aggregate gypsum plaster	22 13

PART 4 FIRE AND LIFE SAFETY

Table 13Framed Construction, Non-Load Bearing (Required to Resist Fire from One Side at a Time) (Clause C-1)

Sl No.	Nature of Construction and Materials/Steel or Timber Frame at Centres not Exceeding 600 mm, Facings on Both Sides of	Stud Construction	Minimum Thickness (mm) of Protection for a Fire Resistance of
Sl No.		Stud Construction	30 min	60 min	90 min	120 min
(1)	(2)	(3)	(4)	(5)	(6)	(7)
i) Dry lining with materials fixed direct to studs, without plaster finish:
	a) One layer of plasterboard with taped and filled joints	Timber or steel	12.7	—	—	—
	b) Two layers of plasterboard with joints staggered, joints in outer layer taped and filled – Total thickness for each face	Timber or steel	19	25	—	—
	c) One layer of asbestos insulating board with transverse joints backed by fillers of asbestos insulating board not less than 9 mm thick, or by timber	Timber or steel	9	12	—	—
	d) One layer of wood wool slabs	Timber	25	—	—	—
	e) One layer of chipboard or of plywood	Timber or steel	18	—	—	—
ii) Lining with materials fixed direct to suds, with plaster finish:
	a) Plasterboard of thickness:
	1) With not less than 5 mm gypsum plaster finish	Timber or steel	9.5	—	—	—
	2) With not less than 13 mm gypsum plaster finish	Timber or steel	—	12.7	—	—
iii) Wet finish:
	a) Metal lath and plaster, thickness of plaster:
	1) Sanded gypsum plaster	Timber or steel	13	—	—	—
	2) Lightweight aggregate gypsum plaster	Timber Steel	—	13	19	25

Table 14Framed External Walls Load Bearing (Required to Resist Fire from One Side at a Time) (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection for a Fire Resistance of 60 min
(1)	(2)	(3)
i)	Timber studs at centres not exceeding 600 mm with internal linings of:Plasterboard layers with joints in outer layer taped and filled, total thickness of plasterboard	31

Table 15Framed External Walls Non-Load Bearing [Required to Resist Fire from Inside the Building (A)] (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection for a Fire Resistance of
Sl No.	Nature of Construction and Materials	30 min(3)	60 min(4)	90 min(5)	120 min(6)	180 min(7)	240 min(8)
i) Steel frame with an external cladding of non-combustible sheets (excluding sheet steel), with a steel supporting framework and internal lining of:
a) Metal lath and plaster, thickness of plaster:
1) Sanded gypsum plaster (metal lathing grade)		13	13	—	—	—	—
2) Lightweight aggregate gypsum plaster		10	13	15	15	15	19
b) Two layer of plasterboard with joints staggered joints in outer layer taped and filled – Total thickness		21	32	—	—	—	—
c) Plasterboard of thickness:
1) With not less than 5 mm gypsum plaster finish		12.7	—	—	—	—	—
2) With not less than 13 mm gypsum plaster finish		9.5	—	—	—	—	—
3) With not less than 10 mm lightweight aggregate gypsum plaster		9.5	—	—	—	—	—
d) One layer of asbestos insulating board with transverse joints backed by fillers of asbestos insulating board not less than 9 mm thick, or by timber		9	9	12	12	12	12
e) One layer of wood/wool slabs without finish		—	50	—	—	—	—
f) One layer of compressed straw building slabs:
1) Without finish		50	—	—	—	—	—
2) With not less than 5 mm gypsum plaster finish		—	50	—	—	—	—
g) Aerated concrete blocks		50	50	63	63	75	100
h) Bricks of clay:
1) Without finish		75	75	90	90	100	100
2) With not less than 13 mm lightweight aggregate gypsum plaster		—	—	75	75	90	90

Table 16Framed External Walls Non-Load Bearing [Required to Resist Fire from Inside the Building (B)] (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection to provide Sufficient Insulation to Achieve a Modified Fire Resistance of Up to 240 min
(1)	(2)	(3)
i)	Steel frame with an external cladding of sheet steel fully lapped, steel bolted and fixed to steel sheeting rails, with timber or steel supporting framework and internal lining of:
	a) Metal lath and plaster, thickness of plaster:
	1) Sanded gypsum plaster (metal lathing grade)	13
	2) Lightweight aggregate gypsum plaster	10
	b) One layer of plasterboard with joints taped and filled	12.7
	c) Plasterboard of thickness with not less than 5 mm gypsum plaster finish	9.5
	d) One layer of asbestos insulating board with transverse joints backed by fillers of asbestos insulating board not less than 9 mm thick, or by timber	9
	e) One layer of wood/wool slabs	25
	f) One layer of compressed straw building slabs	50
	g) One layer of chipboard or of plywood	18
	h) Aerated concrete blocks	50
	j) Bricks of clay	75
	k) Any internal decorative lining with a cavity fill independently supported and retained in position of mineral fibre insulating material (excluding glass) at a density of 48 kg/m3	50

PART 4 FIRE AND LIFE SAFETY

Table 17Framed Walls Non-Load Bearing [Required to Resist Fire from Inside the Building (C)] (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection for a Fire Resistance of 90 min
(1)	(2)	(3)
i) Timber frame with external cladding of weather boarding or external plywood, 9.5 mm with an internal lining of :
a) Plasterboard not less than 9.5 mm thick, finished with:
1) Gypsum plaster		13
2) Lightweight aggregate gypsum plaster		10
b) Plasterboard not less than 12.7 mm thick, finished with:
1) Gypsum plaster		10
2) Lightweight aggregate gypsum plaster		10
c) One layer of asbestos insulating board with transverse joints backed by fillers of asbestos insulating board not less than 9 mm thick, or by timber		9
		12

Table 18Reinforced Concrete Columns (Clause C-1)

Sl No.	Nature of Construction and Materials		Minimum Dimensions (mm) Excluding any Finish, for a Fire Resistance of
Sl No.	Nature of Construction and Materials		30 min	60 min	90 min	120 min	180 min	240 min
(1)		(2)	(3)	(4)	(5)	(6)	(7)	(8)
i)	Fully exposed	a) Width	150	200	250	300	400	450
i)	Fully exposed	b) Cover	40	40	40	40	40	40
ii)	50 percent exposed	a) Width	125	160	200	200	300	350
ii)	50 percent exposed	b) Cover	40	40	40	40	40	40
iii)	One face exposed	a) Thickness	100	120	140	160	200	240
iii)	One face exposed	b) Cover	40	40	40	40	40	40

Table 19Concrete Beams (Clause C-1)

Sl No.	Nature of Construction and Materials			Minimum Dimensions (mm) Excluding any Finish, for a Fire Resistance of
Sl No.	Nature of Construction and Materials			30 min(3)	60 min(4)	90 min(5)	120 min(6)	180 min(7)	240 min(8)
(1)	(2)			30 min(3)	60 min(4)	90 min(5)	120 min(6)	180 min(7)	240 min(8)
i)	Reinforced concrete (simply supported)	a)	Width	200	200	200	200	240	280
i)	Reinforced concrete (simply supported)	b)	Cover	20	20	20	40	$60^{1)}$	$70^{1)}$
ii)	Reinforced concrete (continuous)	a)	Width	200	200	200	200	240	280
ii)	Reinforced concrete (continuous)	b)	Cover	20	20	20	30	40	$50^{1)}$
iii)	Prestressed concrete (simply supported)	a)	Width	100	120	150	200	240	280
iii)	Prestressed concrete (simply supported)	b)	Cover	25	40	$55^{1)}$	$70^{1)}$	$80^{1)}$	$90^{1)}$
iv)	Prestressed concrete (continuous)	a)	Width	80	100	120	150	200	240
iv)	Prestressed concrete (continuous)	b)	Cover	20	30	40	$55^{1)}$	$70^{1)}$	$80^{1)}$

Table 20 Concrete Floors(Clause C-1)
Sl No.	Nature of Construction and Materials		Minimum Dimensions (mm) Excluding any Finish, for a Fire Resistance of
Sl No.	Nature of Construction and Materials		30 min	60 min	90 min	120 min	180 min	240 min
(1)	(2)		(3)	(4)	(5)	(6)	(7)	(8)
i)	Reinforced concrete (simply supported)	a) Thickness	75	95	110	125	150	170
i)	Reinforced concrete (simply supported)	b) Cover	20	20	25	35	$45^{1)}$	$55^{1)}$
ii)	Reinforced concrete (continuous)	a) Thickness	75	95	110	125	150	170
ii)	Reinforced concrete (continuous)	b) Cover	20	20	20	25	35	$45^{1)}$

Require attention to the additional measures necessary to reduce the risk of spalling.

Table 21Concrete Floors: Ribbed Open Soffit (Clause C-1)

Sl No.	Nature of Construction and Materials		Minimum Dimensions (mm) Excluding any Finish, for a Fire Resistance of
Sl No.	Nature of Construction and Materials		30 min(3)	60 min(4)	90 min(5)	120 min(6)	180 min(7)	240 min(8)
i)	Reinforced concrete (simply supported)	a) Thickness of floor	75	95	110	125	150	170
		b) Rib width	125	125	125	125	150	175
		c) Cover	20	20	35	$45^{1)}$	$55^{1)}$	$65^{1)}$
ii)	Reinforced concrete (continuous)	a) Thickness of floor	75	95	110	125	150	170
		b) Rib width	125	125	125	125	150	175
		c) Cover	20	20	20	35	$45^{1)}$	$55^{1)}$

$^{1)}$ Require attention to the additional measures necessary to reduce the risk of spalling.

Table 22Encased Steel Columns, 203 mm × 203 mm (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Dimensions (mm) Excluding any Finish, for a Fire Resistance of
Sl No.	Nature of Construction and Materials	60 min(3)	90 min(4)	120 min(5)	180 min(6)	240 min(7)
i)	Hollow protection (without an air cavity over the flanges):
	a) Metal lathing with trowelled lightweight aggregate gypsum plaster $^{1)}$	13	15	20	32	—
	b) Plasterboard with 1.6 mm wire binding at 100 mm pitch, finished with lightweight aggregate gypsum plaster not less than the thickness specified:
	1) 9.5 mm plaster board	10	15	—	—	—
	2) 19 mm plaster board	10	13	20	—	—
	c) Asbestos insulating boards, thickness of board:
	1) Single thickness of board, with 6 mm cover fillets at transverse joints	—	19	25	—	—
	2) Two layers, of total thickness	—	—	—	38	50
	d) Solid bricks of clay, composition or sand lime, reinforced in every horizontal joint, unplastered	50	50	50	75	100
	e) Aerated concrete blocks	60	60	60	—	—
	f) Solid blocks of lightweight concrete Hollow protection (with an air cavity over the flanges)	50	50	50	60	75

PART 4 FIRE AND LIFE SAFETY

Table 22(Concluded)

(1)	(2)	(3)	(4)	(5)	(6)	(7)
ii) Asbestos insulating board screwed to 25 mm asbestos battens		12	19	—	—	—
iii) Solid protections:
a) Concrete, not leaner than 1:2:4 mix (unplastered):
1) Concrete not assumed to be load bearing, reinforced $^{2)}$		25	25	25	50	75
2) Concrete assumed to be load bearing		50	50	50	75	75
b) Lightweight concrete, not leaner than 1:2:4 mix (unplastered): concrete not assumed to be load bearing, reinforced $^{2)}$		25	25	25	40	60

$^{1)}$ So fixed or designed, as to allow full penetration for mechanical bond.

$^{2)}$ Reinforcement shall consist of steel binding wire not less than 2.3 mm in thickness, or a steel mesh weighing not less than 0.5 kg/m $^{2}$ . In concrete protection, the spacing of that reinforcement shall not exceed 200 mm in any direction.

Table 23Encased Steel Beams, 406 mm × 176 mm (Protection Applied on Three Sides) (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection for a Fire Resistance of
Sl No.	Nature of Construction and Materials	30 min(3)	60 min(4)	90 min(5)	120 min(6)	180 min(7)	240 min(8)
i)	Hollow protection (without an air cavity beneath the lower flange):
	a) Metal lathing with trowelled lightweight aggregate gypsum plaster $^{1)}$	13	13	15	20	25	—
	b) Plasterboard with 1.6 mm wire binding $^{2)}$ at 100 mm pitch, finished with lightweight aggregate gypsum plaster not less than the thickness specified:
	1) 9.5 mm plaster board	10	10	15	—	—	—
	2) 19 mm plaster board	10	10	13	20	—	—
	c) Asbestos insulating boards, thickness of board :
	1) Single thickness of board, with 6 mm cover fillets at transverse joints	—	—	19	25	—	—
	2) Two layers, of total thickness	—	—	—	—	38	50
ii)	Hollow protection (with an air cavity below the lower flange):
ii)	a) Asbestos insulating board screwed to 25 mm asbestos battens	9	12	—	—	—	—
iii)	Solid protection :
	a) Concrete, not leaner than 1:2:4 mix (unplastered):
	1) Concrete not assumed to be load bearing, reinforced $^{3)}$	25	25	25	25	50	75
	2) Concrete assumed to be load bearing	50	50	50	50	75	75
	b) Lightweight concrete $^{4)}$ , not leaner than 1:2:4 (mix) unplastered	25	25	25	25	40	60

So fixed or designed, as to allow full penetration for mechanical bond.

$^{2)}$ Where wire binding cannot be used, expert advice should be sought regarding alternative methods of support to enable the lower edges of the plasterboard to be fixed together and to the lower flange, and for the top edge of the plasterboard to be held in position.

Reinforcement shall consist of steel binding wire not less than $2.3\mathrm{mm}$ in thickness or a steel mesh weighing not less than $0.5\mathrm{kg / m^2}$ . In concrete protection, the spacing of that reinforcement shall not exceed $200\mathrm{mm}$ in any direction.
Concrete not assumed to be load bearing, reinforced.

Table 24Timber Floors – Tongued and Grooved Boarding, or Sheets of Tongued and Grooved Plywood or Wood Chipboard, of not Less than 21 mm Finished Thickness (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection, for a Fire Resistance of
Sl No.	Nature of Construction and Materials	30 min	60 min	120 min
(1)	(2)	(3)	(4)	(5)
i) 37 mm (minimum) timber joists with a ceiling of:
a)	Timber lathing and plaster, plaster of thickness	15	—	—
b)	Metal lathing and plaster, thickness of plaster:
	1) Sanded gypsum plaster (metal lathing grade)	15	—	—
	2) Lightweight aggregate gypsum plaster	13	13	25
c)	One layer of plasterboard with taped and filled joints	12.7	—	—
d)	Two layers of plasterboard with joints staggered, joints in outer layer taped and filled total thickness	19	31	—
e)	One layer of plasterboard not less than 9.5 mm thick, finished with:
	1) Gypsum plaster	5	—	—
	2) Sanded gypsum plaster	13	—	—
	3) Lightweight aggregate gypsum plaster	13	—	—
f)	One layer of plasterboard not less than 12.7 mm thick, finished with:
	1) Gypsum plaster	5	—	—
	2) Lightweight aggregate gypsum plaster	10	—	—
g)	One layer of asbestos insulating board with any transverse joints backed by fillets of asbestos insulating board not less than 9 mm thick, or by timber	9	12	—

Table 25Timber Floors – Tongued and Grooved Boarding, or Sheets of Tongued and Grooved Plywood or Wood Chipboard, of not Less than 15 mm Finished Thickness (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection for a Fire Resistance of
		30 min	60 min	120 min
(1)	(2)	(3)	(4)	(5)
i) 37 mm (minimum) timber joists with a ceiling of:
a) Timber lathing and plaster, plaster of thickness		15	—	—
b) Metal lathing and plaster, thickness of plaster for:
1) Sanded gypsum plaster (metal lathing grade)		15	—	—
2) Lightweight aggregate gypsum plaster		13	13	25
c) One layer of plasterboard with taped and filled joints		12.7	—	—
d) Two layers of plasterboard with joints staggered, joints in outer layer taped and filled total thickness		22	31	—
e) One layer of plasterboard not less than 9.5 mm thick, finish with:
1) Gypsum plaster		5	—	—
2) Sanded gypsum plaster		15	—	—
3) Lightweight aggregate gypsum plaster		13	—	—
f) One layer of plasterboard not less than 12.7 mm thick, finished with:
1) Gypsum plaster		5	—	—
2) Lightweight aggregate gypsum plaster		10	—	—
g) One layer of asbestos insulating board, with any transverse joints backed by fillets of asbestos insulating board not less than 9 mm thick, or by timber		9	$12^{1)}$	—

PART 4 FIRE AND LIFE SAFETY

Table 26Timber Floors – Any Structurally Suitable Flooring of Timber or Lignocelluloses Boards (Clause C-1)

Sl No.	Nature of Construction and Materials	Minimum Thickness (mm) of Protection, for a Fire Resistance of
Sl No.	Nature of Construction and Materials	30 min	60 min
(1)	(2)	(3)	(4)
i) 37 mm (minimum) timber joists with a ceiling of:
a)	Timber lathing and plaster, plaster of thickness	15	—
b)	Metal lathing and plaster, thickness of plaster for :
	1) Sanded gypsum plaster (metal lathing grade)	15	—
	2) Lightweight aggregate gypsum plaster	13	19
c)	One layer of plasterboard with joints taped and filled and backed by timber	12.7	—
d)	Two layers of plasterboard with joints staggered, joints in outer layer taped and filled total thickness	25	—
e)	Two layers of plasterboard, each not less than 9.5 mm thick, joints between boards staggered and outer layer finished with gypsum plaster	5	—
f)	One layer of plasterboard not less than 9.5 mm thick, finish with :
	1) Sanded gypsum plaster	13	—
	2) Lightweight aggregate gypsum plaster	15	—
g)	One layer of plasterboard not less than 12.7 mm thick, finished with :
	1) Sanded gypsum plaster	15	—
	2) Lightweight aggregate gypsum plaster	13	—
h)	One layer of asbestos insulating board with any transverse joints backed by fillets of asbestos insulating board not less than 9 mm thick, or by timber	12	—