Interpreting Point Load Results

Point load requirement for trafficable roofs is defined in NZS 1170 as 1.1 kN, which approximates a 100 kg person on one foot. (Note: many workers carrying tools or equipment exceed this limit.) To allow for statistical variation this is factored by 20% and a test load of 1.32 kN is applied to give a pass/fail.

Type A roof (unrestricted access roofs) is required to withstand a 1.32 kN test load on the rib without deformation or excessive deflection, (serviceability load) and a 2.41 kN strength load.

Type B roof (Restricted access roofs) is required to withstand a 1.32 kN test load in the pan or over two ribs without deformation or excessive deflection, (serviceability load) and a 2.41 kN strength load.

Type C Roof (non-trafficable) is required to withstand a 0.6 kN test load to the pan or over two ribs, and a 1.1 kN strength load. See Roof Traffic.