Setting out
Count for a maximum clear gap
- where
- member count
- clear opening (mm)
- specified maximum gap (mm)
- member width (mm)
- actual gap (mm)
Explain this equation
Finds the fewest members needed so that no clear gap in an opening exceeds a specified maximum, then the actual equal gap.
W is the clear opening, b the member width and gmax the largest gap allowed, all in millimetres. n is the number of members, and g the actual gap.
n members need n + 1 gaps, so nb + (n + 1)g = W. Setting g to gmax and solving for n gives (W − gmax)/(b + gmax). Rounding up with ⌈ ⌉ guarantees every gap is no wider than the limit. The second line then shares the leftover space equally.
A 1000 mm opening with 40 mm members and a 95 mm maximum needs 7 members, giving 90 mm gaps.
Watch out: the maximum gap must come from the design or regulations. This calculator does not confirm compliance. It always uses at least one member.
Choose a whole member count so equal end and internal gaps do not exceed a specified limit.
Enter your values to see the result.
Good to know
Maximum gap is supplied by the design. A gap calculation is not a guarding compliance check. Uses at least one member.
Sources
- Geometry / arithmetic
This is a calculation aid, not a structural design or compliance certificate. Every default is an example, not a specification for your project.