Cable Railings Requirements
Spacing between the cables
The construction code nationwide requires that any opening should be less than 4” and no 4” sphere should pass. Though in cable railing the target opening is usually less than 3 1/2” taking into account the cables deflection when a 4” ball is forced to go through the cables. In order to meet this requirement, typically the number of parallel cables for 36” high railing is 10 and 12 for 42” high railing.
The recommended posts spacing is 5 feet center to center for 36” high railing and 4 feet for 42” high railing.
Unlike other type of railings, cable railing posts are subjected to the pulling force of the cables. The posts needs to be strong enough to sustain this force.
Top Rail Strength
The IRC code requires the top rail to be able to sustain a concentrated of 200 lbs applied horizontally or vertically down at any point on the top rail. Some local codes specify a smaller load of 20 lbs per linear foot.
Type of Top Rail
The top rail is recommended to be made of steel. In cases where wood is the selection, a steel bar is recommended to be mounted under the wood for additional support.
The total minimum height required varies per building codes depending on the area and target use of either residential or commercial. Local city codes supersede state, national and international code. In most states the residential codes is 36” height. There are some exceptions though like in California the required height for residential railing is 42”. The commercial building code requires the railing to be at a minimum of 42” height. Posts can be floor mounted or fascia/side mounted though the height of the railing is measured from the floor to the top of the railing.
Field Measurements: Where handrails and railings are indicated to fit to other construction, check actual dimensions of other construction by accurate field measurements before fabrication; show recorded measurements on final shop drawings.
Where field measurements cannot be made without delaying the railing fabrication and delivery, obtain guaranteed dimensions in writing by the Contractor and proceed with fabrication of products to not delay fabrication, delivery and installation.
Coordinate fabrication and delivery schedule of handrails with construction progress and sequence to avoid delay of railing installation.