1) Classification for preservation based on durability tests, etc.Class:I — Average life more than 120 months;II — Average life 60 months and above but less than 120 months; andIII — Average life less than 60 months.2) Treatability Grades:a — Heartwood easily treatable;b — Heartwood treatable, but complete penetration not always obtained; in case where the least dimension is more than 60 mm;c — Heartwood only partially treatable;d — Heartwood refractory to treatment; ande — Heartwood very refractory to treatment, penetration of preservative being practically nil even from the ends.3) Classifications based on seasoning behaviour of timber and refractoriness with respect to cracking, splitting and drying rate:A — Highly refractory (slow and difficulty to season free from surface and end cracking);B — Moderately refractory (may be seasoned free from surface and end cracking within reasonably short periods, given a little protection against rapid drying conditions); andC — Non-refractory may be rapidly seasoned free from surface and end-cracking even in the open air and sun. If not rapidly dried, they develop blue stain and mould on the surface.4) Species thus marked and tested from other localities show higher strength to enable their categorization in higher group.For Example:i) Sal tested from W. Bengal, Bihar, U.P. and Assam can be classified as Group ‘A’ species;ii) Haldu tested from Bihar can be classified as Group ‘B’ species;iii) Morus laevigate (Bole) of Assam can be classified in Group ‘B’ species.
Table 2Permissible Lateral Strengths (in Double Shear) of Nails 3.55 mm Dia (9 SWG), 80 mm Long (Clause 4.3)
Sl No.
Species of Wood
For Permanent Construction Strength per Nail
For Temporary Structures Strength per Nail (For Both Lengthening Joints and Node Joints)
Botanical Name
Trade Name
Lengthening Joints N×102
Node Joints N×102
(1)
(2)
(3)
(4)
(5)
N×102 (6)
i)
Albies pirdrow
Fir
8
2
12
ii)
Acacia catecha
Khair
20
17.5
37.0
iii)
Acacia nilotica
Babul
15
11
32.5
iv)
Acrocarpus fraxinifolius
Mundani
18
9.5
19.5
v)
Adina cordifolia
Haldu
23.5
10
22
vi)
Albizia lebbeck
Kokko
20
7
24
vii)
Albizia odoratissima
Kala siris
14
5
22
viii)
Anogeissus latifolia
Axlewood
20
10
29
ix)
Aphanamixis polystachya
Pithraj
19
9
19
x)
Azadiratchta indica
Neem
22
11.5
19
xi)
Balanocarpus utilis
Karung
17.5
21
32
xii)
Bischofia javnica
Uriam
13
6.5
18
xiii)
Betula alnoides
Birch
13
12
22.5
xiv)
Boswellia serrata
Salai
12
5
14.5
xv)
Calophyllum spp.
Poon
16
9
21
xvi)
Canarium euphyllum
White dhup
9
8
10.5
xvii)
Castanopsis hystrix
Indian chestnut
18
10.5
23.5
xviii)
Cedrus deodara
Deodar
9
4
15
xix)
Chukrasia tabularis
Chikrassy
24
8
27
xx)
Cinnamomum spp.
Cinnomon
12
9
13
xxi)
Cullenia rosaana (Syn. Cullenia excalsa)
Karani
11.5
5
19
xxii)
Cupressus torulosa
Cypress
6
5
18
xxiii)
Dalbergia latifolia
Rosewood
19
8.5
23
xxiv)
Dalberia sissoo
Sissoo
14.5
7.5
19
xxv)
Dipterocarpus macrocarpus
Hollong
17
7
20
xxvi)
Dipterocarpus spp.
Gurjan
19
9
19.5
xxvii)
Dillenia pertagyna
Dillenia
16.5
12
16
xxviii)
Diospyros melanoxylon
Ebony
26.5
10
30.5
xxix)
Duabanga grandiflora
Lampati
15
5
12
xxx)
Dysoxylum binectariferum
White Cedar
7.5
5
14.5
xxxii)
Eucalyptus eugenoides
Eucalyptus
17
10
30
xxxii)
Garuga pinnata
Garuga
11.0
7.5
21.0
xxxiii)
Gmelina arborea
Gaman
8
4
9.5
xxxiv)
Grerillea robusta
Silver oak
12.0
7.0
10.5
xxxv)
Grewia tilifolia
Dhaman
13
5
24
xxxvi)
Lagerstroemia spp.
Jarul
24.5
21.5
22.5
xxxvii)
Holoptelea integrifolia
Kanju
12.5
9.5
20.5
xxxviii)
Hopea parviflora
Hopea
31.5
13
28.5
xxxix)
Lagerstroemia spp.
Lendi
19
5
26
xl)
Madhuka Logifera (Syn. Barfia Latifolia)
Mahua
23
7.5
26
xli)
Mangifera indica
Mango
11
9
16
xlii)
Maniltoa polyandra
Ping
26
23.5
32
xliii)
Mesua ferrea
Mesua
26
8
41
xliv)
Michelia spp.
Champ
13
9
20
xlv)
Millingtonia spp.
Phulsopa
10.5
6
17
xlvi)
Morus alba
Mulberry
13
10.5
22.5
xlvii)
Melia azedarach
Persian lilac (bakain)
10.5
2.5
10.5
xlviii)
Morus alba
Mulberry
13
10.5
22.5
xlix)
Ougeinia oojeinensis
Sandan
17
11
18
l)
Phoebe spp.
Bonsum
12
6
13
li)
Pinus roxburghii
Chir
11
10
16
lii)
Pinus wallichiana
Kail
7
3
9
liii)
Planchonia andamanica
Red bombwe
14
13
29
liv)
Planchonia valida (Syn. P. andamonica)
Red bombwe
14.5
13
29.5
lv)
Poeciloneuron indicum
Ballagi
16
7
15.5
lvi)
Populus deltoides
Poplar
16
11.5
17.5
lvii)
Protium serratum (Syn. Burserra Serrata) A.P.
-
25.5
7.0
22.5
lviii)
Pterocarpus marsupium
Bijasal
15
12
27
lix)
Pterocarpus dalbergiodes
Pauduak
19
14
23
lx)
Quercus spp.
Oak (Assam)
21
10
37.5
lxi)
Quercus spp.
Oak (U.P.)
11
10.5
26.5
lxii)
Scheichera cleosa
Kusum
23
16
39.5
lxiii)
Schima wallachi
Chillauni
19.5
9.5
25.5
lxiv)
Shorea assamica
Makai
12.5
7.5
15.0
lxv)
Shorea robusta
Sal (M.P.)
23
15.5
19.5
PART 6 STRUCTURAL DESIGN — SECTION 3 TIMBER AND BAMBOO: 3A TIMBER
Table 2(Concluded)
(1)
(2)
(3)
(4)
(5)
(6)
lxvi)
Shorea robusta
Sal (U.P.)
10
5
19
lxvii)
Stereospenmum chelonoides
Padriwood
16
8
19.5
lxviii)
Syzygium spp.
Jamum
15
12
25
lxix)
Tectona grandis
Teak
14
8
13
lxx)
Terminalia alata
Sain
16
16
29
lxxi)
Terminalia arjuna
Arjun
8.5
7
16.5
lxxii)
Terminalia bellirica
Bahera
10
10
14
lxxiii)
Terminalia biolata
White chuglam
18
9
21
lxxiv)
Terminalia chebula
Myrobalan
16.5
5.5
22.5
lxxv)
Terminalia procera
Badam
18
10.5
20
lxxvi)
Terminalia manii
Black chuglam
23
10
33
lxxvii)
Terminalia myriocarpa
Hollock
13
10
19.5
lxxviii)
Toona spp.
Toona
10
8
21
lxxix)
Xylia xylacarpa
Irul
23
6
33
lxxx)
Toona ciliata
Toon
16
9
21
NOTES
1 Nails of 3.55 mm (9 SWG) diameter are most commonly used. The above values can also be used for 4 mm (8 SWG) diameter 100 mm long nails.
2 The values in Newton (N) are approximate converted values from kgf. For exact conversion the value is 1 kgf = 9.806 65 N.
3 Preboring of nail-jointed timber construction is desirable and shall be done in accordance with good practice as in, 6.2.2 and Table 3 of good practice [6-3A(7)].
Table 3Permissible Lateral Strengths (In Double Shear) of Nails 5.00 mm Dia (6 SWG), 125 mm and 150 mm Long
Sl No.
Species of Wood
For Permanent Construction Strength per Nail
For Temporary Structures Strength Per Nail (For Both Lengthening Joints and Node Joints) N × 102(6)
Botanical Name
Trade Name
Lengthening JointsN × 102(4)
Node JointsN × 102(5)
(1)
(2)
(3)
i)
Abies pindrow
Fir
16.5
4.5
21
ii)
Acacia catechu
Khair
42
25
71.5
iii)
Acacia nilotica
Babul
27
13.5
53
iv)
Alibizia procera
Safed siris
35
18
-
v)
Alibizia odoratissima
Kala siris
27.5
17.5
45
vi)
Alstonia scholaris
Chatian
9.5
5.5
27
vii)
Anogeissus latifolia
Axlewood
22.5
13
46.5
viii)
Azadirachata indica
Neem
23.5
16
47
ix)
Cupressus torulosa
Cypress
20
7
27
x)
Cullenia rosayroana
Karani
11
9.5
30
xi)
Dalbergia sissoo
Sissoo
17
15
43
xii)
Diptrocarous spp.
Gurjan
19.5
9.5
33
xiii)
Eucalyptus Prob. E. Tereticornis
—
37.5
28.5
47
xiv)
Hardwickia binata
Anjan
32
19
59
xv)
Hopea perviflora
Hopea
60.5
25
61.5
xvi)
Holoptelea integrifolia
kanju
18
12.5
37.5
xvii)
Mangifera indica
Mango
22.5
15
32
xviii)
Mesua ferrea
Mesua
24
15.5
57.5
xix)
Michelia champaca
Champ
26
12.5
39
xx)
Pterocarpus marsupium
Bijasal
20.5
15
43
xxi)
Pinus roxburghii
Chir
9
6
24
xxii)
Shorea robusta (U.P.)
Sal
19.5
17
37
xxiii)
Shorea robusta
Sal
30.5
20
41
xxiv)
Schleichera cleosa
Kusum
15
14
55
xxv)
Stereospimum personatum
Padriwood
22
8
34
xxvi)
Syzygium cumini
Jamum
18
14.5
38.5
xxvii)
Terminalia myriocarpa
Hollock
27.5
9
41
xxviii)
Tectona grandis
Teak
28
13
30
xxix)
Toona ciliata
Toon
19
7
32.5
xxx)
Hopea utilis
Karung kangoo
31
10
58
xxxii)
Phoebe spp.
Bonsum
20
7.5
30
xxxiii)
Pterocarpus dalbergiodes
Padauk
27.4
13.4
37.7
xxxiii)
Populus deltoides
Poplar
21
15
38.5
NOTES
1 Nails of 5.00 mm diameter are most commonly used.
2 The values in Newton (N) are approximate converted values from kgf. For exact conversion the value is 1 kgf = 9.806 65 N.
3 Preboring of nail-jointed timber construction is desirable and shall be done in accordance with good practice as in, 6.2.2 and Table 3 of good practice [6-3A(7)].
For detailed zonal classification in the country, tolerances, etc, reference may be made to good practice [6-3A(4)].
Doors and windows: a) 50 mm and above in thickness
10
12
14
16
b) Thinner than 50 mm
8
10
12
14
iii)
Flooring strips for general purposes
8
10
10
12
iv)
Flooring strips for tea gardens
12
12
14
16
NOTE — The country has been broadly divided into the following four zones based on the humidity variations in the country:
Zone I — Average annual relative humidity less than 40 percent
Zone II — Average annual relative humidity 40 to 50 percent
Zone III — Average annual relative humidity 50 to 67 percent
Zone IV — Average annual relative humidity more than 67 percent