How Bolts are Selected from the Specification

The steps in selecting a bolt from the Specification are as follows:

1. For each bolt in the set, get the BTYP values for each end of the bolt:

   • If they are both set to BOLT, select the default bolt for that bolt diameter.

   • If they match and are not set to BOLT, select the bolt with that BTYP.

   • If they do not match, and one value is set to BOLT, select the bolt with BTYP set to the other BTYP.

   • If they do not match and neither is set to BOLT, select the bolt with BTYP set to the BTYP of the start of the bolt.

2. Set the bolt item code from the bolt SPCOM name, and the bolt description from its detail and material texts.

3. Go to the SBOLT given by the BLTREF of the SPCOM:

   • Get the values of BTYPs for items such as nuts and washers from the BITEMS array.

   • Get the length values of these items from the BLIST array

   • Get the extension thread length from the XLEN attribute.

4. For each STYP selector, select the item by its BTYP and the current bolt’s BDIA. Get its item code from its SPCOM name and its description from its detail and material texts.

5. Add its length to the accumulated bolt length.

6. Add the extension thread length to the accumulated bolt length

7. Go to the NSTD length table. If the accumulated length is within 1mm over an available length from the BLEN array, then round down, else round up. If the NSTD reference is NULL, use the actual BLEN of the SBOLT, since this is intended as a pre-set length for special purposes, for example, a large flange with exact torque requirements.

8. Include the bolt length in the item code and description in accordance with the existing Isodraft options.

When the bolt member count has been satisfied, combine the data to obtain totals of like bolt items in the material list. See Bolting Information. Any error conditions such as a bolt item cannot be selected, or there are no long enough lengths in the NSTD table, will cause the system to generate an error message, output a material description of ‘‘Bolts undefined" for that joint (with zero item code, size and quantity), and continue detailing.