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34 <strong>JJI</strong>-JOIST PITCHED RAFTERS<br />
Joist Type<br />
Dead load up to 0.5kN/m 2 Dead load up to 1.0kN/m 2 Dead load up to 1.5kN/m 2<br />
15˚ 30˚ 45˚ 15˚ 30˚ 45˚ 15˚ 30˚ 45˚<br />
<strong>JJI</strong> 145 A+ 3255 3092 3525 2840 2694 2938 2568 2437 2597<br />
<strong>JJI</strong> 195 A+ 4703 4440 4608 4046 3814 3854 3639 3430 3415<br />
<strong>JJI</strong> 195 B+ 5283 5046 5129 4579 4316 4283 4096 3861 3791<br />
<strong>JJI</strong> 195 C 5581 5333 5426 4883 4603 4528 4356 4107 4005<br />
<strong>JJI</strong> 195 D 6289 6014 6134 5517 5249 5109 4974 4690 4511<br />
<strong>JJI</strong> 220 A+ 5259 5018 5086 4577 4308 4257 4108 3866 3776<br />
<strong>JJI</strong> 220 B+ 5912 5644 5730 5207 4937 4790 4683 4407 4243<br />
<strong>JJI</strong> 220 C 6151 5874 5968 5415 5142 4986 4894 4606 4414<br />
<strong>JJI</strong> 220 D 6855 6551 6668 6024 5726 5563 5457 5174 4919<br />
<strong>JJI</strong> 235 A+ 5536 5281 5349 4870 4581 4480 4367 4106 3975<br />
<strong>JJI</strong> 235 B+ 6212 5929 6015 5474 5196 5031 4965 4669 4459<br />
<strong>JJI</strong> 235 C 6471 6177 6271 5699 5411 5243 5174 4885 4644<br />
<strong>JJI</strong> 235 D 7213 6891 7009 6343 6027 5850 5750 5450 5176<br />
<strong>JJI</strong> 245 A+ 5715 5451 5520 5046 4757 4624 4535 4262 4103<br />
<strong>JJI</strong> 245 B+ 6396 6104 6190 5639 5352 5179 5124 4831 4591<br />
<strong>JJI</strong> 245 C 6678 6374 6469 5884 5586 5409 5344 5060 4793<br />
<strong>JJI</strong> 245 D 7454 7120 7239 6557 6230 6044 5947 5635 5349<br />
<strong>JJI</strong> 300 A+ 6681 6369 6440 5906 5598 5401 5379 5084 4798<br />
<strong>JJI</strong> 300 B+ 7398 7056 7144 6533 6195 5985 5945 5622 5312<br />
<strong>JJI</strong> 300 C 7792 7433 8395L 6876 6523 6306 6254 5916 5594<br />
<strong>JJI</strong> 300 D 8750 8352 8395L 7709 7319 7087 7002 6629 6280<br />
<strong>JJI</strong> 350 C 8825 8416 8395L 7794 7391 7138 7094 6708 6336<br />
<strong>JJI</strong> 350 D 9813 9362 8395L 8655 8212 7943 7869 7446 7044<br />
<strong>JJI</strong> 400 C 9908 9447 8395L 8755 8300 8011 7972 7536 7114<br />
<strong>JJI</strong> 400 D 10730 10234 8395L 9473 8984 8395L 8619 8152 7704<br />
<strong>JJI</strong> 450 D 11488 10302L 8395L 10150 9623 8395L 9242 8737 8249<br />
Table 20. Maximum Engineering Spans for <strong>JJI</strong>-Joist Pitched Rafters @ 400mm c/c<br />
Joist Type<br />
Dead load up to 0.5kN/m 2 Dead load up to 1.0kN/m 2 Dead load up to 1.5kN/m 2<br />
15˚ 30˚ 45˚ 15˚ 30˚ 45˚ 15˚ 30˚ 45˚<br />
<strong>JJI</strong> 145 A 3255 3092 3525 2840 2694 2938 2568 2437 2597<br />
<strong>JJI</strong> 195 A 4612 4355 4537 3973 3746 3795 3576 3371 3364<br />
<strong>JJI</strong> 195 B 5175 4939 5021 4468 4212 4195 4002 3772 3714<br />
<strong>JJI</strong> 220 A 5159 4920 4987 4474 4212 4175 4020 3783 3704<br />
<strong>JJI</strong> 220 B 5827 5563 5646 5133 4855 4721 4608 4336 4182<br />
<strong>JJI</strong> 235 A 5434 5183 5248 4765 4482 4396 4276 4021 3901<br />
<strong>JJI</strong> 235 B 6120 5841 5925 5395 5120 4956 4884 4593 4393<br />
<strong>JJI</strong> 245 A 5614 5354 5420 4956 4659 4541 4445 4177 4031<br />
<strong>JJI</strong> 245 B 6296 6008 6091 5552 5268 5097 5046 4747 4519<br />
<strong>JJI</strong> 300 A 6583 6275 6344 5819 5516 5321 5302 5010 4727<br />
<strong>JJI</strong> 300 B 7257 6920 7004 6409 6077 5869 5833 5516 5210<br />
Table 20a. Maximum Engineering Spans for <strong>JJI</strong>-Joist Pitched Rafters @ 400mm c/c – A & B Range<br />
Notes for Tables 19, 19a, 20 and 20a:<br />
1. These tables serve as guidance only. For a more detailed <strong>JJI</strong>-Joist appraisal contact a <strong>JJI</strong>-Joist Distributor<br />
2. To achieve the stated spans, adequate <strong>JJI</strong>-Joist bearing will be required. Web stiffeners may be necessary<br />
3. Figures followed by L denote engineering spans limited by the maximum manufactured <strong>JJI</strong>-Joist length of 12m<br />
4. Designs based on the dead load as shown + 0.75kN/m 2 imposed snow load up to 30° pitch reducing linearly thereafter to zero at 60° pitch (additional<br />
imposed loads may apply – seek Roof Designer guidance)<br />
5. For roof pitches of 30° or less a short term man load of 0.9kN is applied to the middle of the rafter span to account for construction and maintenance loading.<br />
For steeper pitches it is assumed that a roof ladder would spread the load<br />
6. Spans assume the rafter top flange is laterally restrained at maximum 400mm c/c using battens or rigid sarking<br />
7. Permissible web holes to be drilled in accordance with JoistMaster software<br />
8. Design in accordance with BS 6399-3-4.3.1 (Minimum imposed load on roof with no access)<br />
9. No allowance for rafter overhangs within table
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