PURLIN is a computer program for the analysis and design of lipped and unlipped channel, zed and hat section purlins. The sections can be designed with or without roof sheeting attached. Zed sections with roof sheeting can also be designed by modelling the section as an equivalent channel section. PURLIN can also design Fielders Cee sections (same shape as the NZ Dimond section) and also allows the design of back to back and boxed channels. The program can also design any symmetric or monosymmetric section by the direct strength method. The user can also edit the section library and input different size sections and steel grades.

The user can select purlin configurations from one to twelve spans with cantilevers at either or both ends. Purlin systems with two or more spans can be lapped or unlapped. In addition, up to three rows of bridging can be included in each span. The effects of load height and restraint caused by roof sheeting on flexural-torsional buckling are also taken into account. The structure can be analysed for different combinations of point and uniformly distributed load and for different axial loads in each span.

Strength limit state design load capacities for section moment capacity, flexural-torsional buckling moment capacity, distortional buckling moment capacity, shear capacity, combined moment and shear capacity, bearing capacity, combined moment and bearing capacity, axial tension and compression capacity, combined axial load and moment capacity, and connection capacity are calculated. The direct strength method can also be used to calculate the load capacity. A serviceability limit state design load capacity is also calculated.



Setup file

Copy protection and purchasing

The program PURLIN is copy-protected to prevent unauthorised copying of the program.

If the user wishes to purchase the program, a site key must be obtained. To obtain a site key, the user must supply the site code for their computer. The site code is obtained by pressing ENTER when the PURLIN splash screen appears after starting the program. When the site key is typed in and Validate is pressed, the user will have a fully licensed copy of PURLIN.


Single-user licence – $2,000 + GST

Multi-user licence (5 copies) – $4,000 + GST