Portable ladders -accessories: Strength and stiffness, safety for users (NT MECH 021) Posted onApril 25, 1990September 25, 2020Author Report #: NT MECH 021 Approved: April 1990 Download pdf Size: 161.74 KB Abstract The aim of this test method is to ensure that ladder accessories fulfil reasonable requirements with respect to strength, stiffness and safety. Categories and tags