Australian Standard AS1657-2018

 Basic dimensions

• The maximum height a step ladder can extend between landing is 6 m
• Step ladders incline angle nominally between 60° and 70°.
• The width of the step ladder between the stiles is  450mm to 750mm.

Clearances

• The minimum clearance required for a step ladder is 200mm from the nosing of the tread to any structure behind it.
• Front clearance shall be a distance of 900mm parallel to the nosing slope when the ladder is inclined at 70° and 1000mm when the ladder is inclined at 60°.
• Minimum headroom is typically 2000 mm, this may need to be increased if helmets are worn.

Dimensions of treads

• Treads depth min 100 mm. The surface of every tread shall be slip-resistant.
• Treads shall be equally spaced at distances between 200 mm to 300 mm within a tolerance of ±5 mm.
• The top tread shall be level with, or be integrated into, the landing.
• The maximum permissible cross-slope at bottom landing is 7°

Handrails

• Handrails shall be provided on each side of the step ladder, with clearance between the handrails 550mm to 750mm.
• The bottom of the handrails shall commence at a point no more than 900 mm above the landing.
• handrails distance shall be 150mm to 200mm measured perpendicular from the nosing of the treads.

Landing

• The width of the landing shall be not less than the width of the ladder or 600 mm, whichever is the greater.
• Landing length shall provide standing space ≤600 mm clear of cross-traffic, door swing or any other structure.
• Top landing length shall be ≤900 from the front of the ladder.

Protection from fall

• The maximum height a step/rung ladder can extend between landing is 6 m. For vertical distance greater than 6m multiple step/rung ladders with an intermediate landings are required.  To limit the distance a person could fall, a change of direction by 180°, or staggering at each landing is required. All ladders are to be same in multiple-flight ladders.
• Where a person could fall more than 6 m to a level below, the step ladder must be fitted with a side screen, or a ladder cage to prevent fall.
• Where the above measures cannot be practicable other means can be implemented such as utilising a fall-arrest system complying with AS/NZS 1891.

LOADING

• Refer to the standard.