Published Date: July 01, 2009
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Section 130 Design criteria
A fixed ladder is a ladder that is an integral part of a building or structure. It is usually vertical but can be as much as 15° from the vertical. A fixed ladder cannot lean back. Figure 8.2 shows a fixed ladder with a walkthrough at the top, and a similar ladder equipped with a ladder cage.
A ladder cage is a permanent structure attached to a ladder to provide a barrier between the worker and the surrounding space. It serves to support a worker if the worker needs to rest against a barrier. A ladder cage is not a means of fall protection.
Figure 8.2 Fixed ladder with walkthrough at top (left); same ladder with cage(right)
Process Industry Practices (PIP) Standard STF05501 (February 2002), Fixed Ladders and Cages, published by the Construction Industry Institute, specifies the design details for fabrication and installation of typical fixed ladders for structures, miscellaneous platforms, and vessels for regular operational entry and exit. These details are intended to be issued to fabricators supplying these ladders and to the erectors for use in installations.
A sample copy of the Standard can be viewed at the following website address:
Table 8.1 summarizes some of the most important differences between the requirements of the PIP Standard and the fixed ladder requirements that were in effect prior to when the first edition of the OHS Code went into effect on April 30, 2004. The requirement to comply with the PIP Standard is not retroactive to fixed ladders installed prior to the effective date of the first edition of the OHS Code.
The PIP standard referenced in this section is intended to be used as a design standard i.e. one which can be directly referenced by an employer or owner. A fabricator can then fabricate the fixed ladder as described in the standard’s mechanical drawings. To comply with the OHS Code, all the dimensional and strength requirements of the PIP standard must be met.
Some fabricators and employers have liberally interpreted subsection 130(2) of the OHS Code, suggesting that the PIP standard functions as no more than a design guideline. These parties have chosen to interpret the subsection as meaning that as long as “established engineering principles” are followed, the dimensions specified in the PIP standard need not be met. This is an incorrect interpretation of the words.
The phrase “established engineering principles” refers to the “material and process standards” referenced in the PIP standard. The reason for using this phrase is that the PIP Standard refers to material and process standards that reflect practices followed in the U.S. These standards may not be appropriate for use in Alberta. As a result, an employer may use applicable Canadian material and process standards.
There have been a couple of cases in which a minor dimensional difference has been discovered during commissioning following installation of a fixed ladder. In these cases employers have requested an “acceptance”. This is a letter granted to the employer by Workplace Health and Safety stating that the ladder in question “functionally” complies with the OHS Code. In each case the employer had to prove that the ladder with the dimensional error provided workers with a level of safety that was equal to or greater than that provided by a ladder meeting all of the PIP standard’s dimensional requirements.
In each case to date the dimensional difference was minor and did not compromise worker safety. An acceptance was granted in each case. One of these acceptances resulted in the addition of paragraph 130(2)(b) to this edition of the OHS Code. Recognizing that larger workers and workers wearing safety or rescue equipment may have difficulty passing through the ladder cage hoops, the allowable hoop dimension has been increased. The inside diameter of a cage hoop can now be as much as 760 mm. The existing dimensions shown in Section B-B of the PIP standard limit the width to 686 mm and the depth to 696 mm. If an employer uses the 760 mm dimension, then other dimensional measurements associated with the fixed ladder may need to be altered to accommodate the larger cage hoops.
The PIP Standard specifies that the fixed ladder must be made of steel. Situations may arise in which steel is not the preferred material of choice e.g. exposure to chemicals. Fixed ladders made of aluminum or fiberglass are available. If a fixed ladder is made of a material other than steel, the employer must ensure that the design is certified by a professional engineer as being as strong as or stronger than that required by PIP Standard STF05501.
Subsections 130(4) and 130(5)
Ladderway floor openings and platforms are normally guarded by a standard guardrail and toe board on all exposed sides, except at the entrance to the opening (see subsection 321(5)). A self-closing double bar safety gate or equally effective means must be provided at the opening to prevent persons from walking directly into the opening and falling.
A safety gate is not required at landings.
An access ladder attached to a scaffold is subject to the requirements of section 327, not the requirements of section 130.
Table 8.1 Comparison of selected fixed ladder design requirements
Requirements Prior to April 30, 2004
|Rung spacing||250 millimetres min
305 millimetres max
|Clearance between ladder rungs and structure to which ladder is affixed (hand and toe clearance)||150 millimetres min||178 millimetres; when distance to any unavoidable object, including insulation, is less than 178 millimetres, the minimum clearance is 39 millimetres|
|Platform spacing intervals and dimensions||6.5 metres (21.5 feet); 760 millimetres x 760 millimetres (platforms not required if the ladder incorporates a fall arrest system)||9.1 metres (30 feet); 762 millimetres x 762 millimetres (platforms not required if the ladder incorporates a fall arrest system)|
|Ladder cage||Required if the ladder is more than 6.5 metres (21.5 feet) long (cage not required if the ladder incorporates a fall arrest system)||Required on ladder having a minimum unbroken length of 6.1 metres (20 feet); (cage not required if the ladder incorporates a fall arrest system)|
|Ladder length||Not specified||Max unbroken length of 9.1 metres (30 feet) unless ladder incorporates a fall arrest system|
|Lowest point of ladder cage||No more than 3 metres (10 feet) above landing or ground||Within 2.1 metres (7 feet) to 2.4 metres (8 feet) of the walking surface|
|Ladderway opening||Not specified||Requires safety gate or equivalent means|
|Width of rungs between rails||Not specified||450 millimetres|