Scaffolds - Suspended

Scaffolds are temporary structures that consist of one or more elevated platforms used where work cannot be done on or from the ground, from a building or other permanent structure without hazard to the workers.   Suspended scaffolds consist of one or more platforms suspended from a permanent or temporary structure overhead structure by non-rigid components, such as ropes and wire cables.


Scaffolds can be grouped in two main types: supported and suspended.  This topic discusses suspended scaffolds.

There are several types of suspended scaffolds, but all of them have the same main components:

  • Work Platform
  • Suspension system
  • Guard rails

A suspended scaffold or suspended platform must be designed based on good engineering practices, , and scaffold-specific requirements prescribed by the regulations.

Types of suspended scaffolds include:

  • Two-point suspended scaffold (swing stage) – One or more work platforms suspended by two ropes from an overhead fixed support and equipped with equipment that permits the up and down movement. It is the most used suspended scaffold.
  • Single point suspended adjustable scaffold/boatswain chair – A platform suspended only by one rope from an overhead support and equipped with means to permit the platform to move vertically.

Structural requirements for single and two-point suspended scaffolds include:

  • The overhead fixed support or outrigger beams must be capable to support at least four times the maximum load to which it may be subjected.
  • The outrigger beam must be secured against vertical and horizontal movement and must be tied back to the fixed support by a secondary line. The lines must each be capable of supporting the weight of the suspended load and of the supporting system.
  • The distance between the outrigger scaffold and the wall behind is not greater than 75 millimetres.
  • Specially designed and manufactured counterweights with affixed legible instruction for use should be securely attached to the outrigger beams.
  • Stacked or tiered suspended scaffolds must have at least two independent means of support that would not fail at the same time.
  • A boatswain’s chair must be at least 600 millimetres long and 250 millimetres wide and must be supported by wire rope of at least nine millimetres if the worker is using corrosive substances, flame-cutting or mechanical-grinding equipment.

Multi-point suspended work platforms – means a suspended work platform more than 750 millimetres in width or a system of suspended work platforms in which any one platform is more than 750 millimetres in width that is supported from an overhead fixed support system by at least three primary load-carrying means of suspension to maintain the stability of the work platform or system of work platforms.

Multi-point suspended scaffold

A multi-point suspended scaffold must be designed by a professional engineer.

The design requirements for multi-point suspended work platforms are complex. At minimum, the design must meet the criteria as set out in the regulations. The platforms must be designed in such a way that the failure of one means of support will not trigger the collapse or fail of any part of the platform even in the most adverse loading conditions including that the load factors, live and dead factors, and the safety factors will not be affected.

The design drawings must include a statement attesting that the design meets the regulatory requirements, and information about the grade of the materials, component specification, loads and safety factors; and procedures for erecting, dismantling, traversing or moving the equipment.

Construction Projects
O. Reg. 213/91

Part I GENERAL

Section 1

1. (1) In this Regulation,

"adequate", in relation to a procedure plan, material, device, object or thing, means,

(a) sufficient for both its intended and its actual use, and

(b) sufficient to protect a worker from occupational illness or occupational injury,

and "adequately" has a corresponding meaning;

"allowable unit stress", in relation to a material, means,

(a) the allowable unit stress assigned to a material by the standards required under Ontario Regulation 413/90 (the "Building Code"), or

(b) if no allowable unit stress is assigned under clause (a), the allowable unit stress for the material as determined by a professional engineer in accordance with good engineering practice;

"approved", in relation to a form, means approved by the Minister;

"blocker truck" means a truck that weighs at least 6,800 kilograms and has four-way flashers and a mounted flashing arrowboard sign;

"boom" means the projecting part of a backhoe, shovel, crane or similar lifting device from which a load is likely to be supported;

"Building Code" Repealed. [O. Reg. 345/15, s. 1]

"caisson" means,

(a) a casing below ground or water level whether or not it is designed to contain air at a pressure greater than atmospheric pressure,

(b) an excavation, including a water well but not a well within the meaning of the Oil, Gas and Salt Resources Act , drilled by an auger and into which a person may enter;

"cofferdam" means a structure constructed entirely or partially below water level or below the level of the groundwater table and intended to provide a work place that is free of water;

"competent worker", in relation to specific work, means a worker who,

(a) is qualified because of knowledge, training and experience to perform the work,

(b) is familiar with the Occupational Health and Safety Act and with the provisions of the regulations that apply to the work, and

(c) has knowledge of all potential or actual danger to health or safety in the work;

"conduit" means a sewer, a water main, a duct or cable for a telegraphic, telephonic, television or electrical service, a pipe or duct for the transportation of any solid, liquid or gas or any combination of these items and includes a service connection made or intended to be made thereto;

"confined space" Repealed. [O. Reg. 628/05, s. 1]

"Construction Health and Safety Branch" Repealed. [O. Reg. 145/00, s. 1]

"crash truck" means a blocker truck that is equipped with a crash-attenuating device;

"critical weld" means, in relation to a suspended work platform, a weld the failure of which could result in the complete or partial collapse of the suspended work platform;

"excavation" means the hole that is left in the ground, as a result of removing material;

"excavation depth" means the vertical dimension from the highest point of the excavation wall to a point level with the lowest point of the excavation;

"excavation width" means the least horizontal dimension between the two opposite walls of the excavation;

"fall arrest system" means an assembly of components joined together so that when the assembly is connected to a fixed support, it is capable of arresting a worker's fall;

"fall restricting system" means a type of fall arrest system that has been designed to limit a worker's fall to a specified distance;

"falsework", in relation to a form or structure, means the structural supports and bracing used to support all or part of the form or structure;

"fixed support" means a permanent or temporary structure or a component of such a structure that can withstand all loads and forces the structure or component is intended to support or resist and is sufficient to protect a worker's health and safety, and includes equipment or devices that are securely fastened to the structure or component;

"flammable liquid" means a liquid with a flash point below 37.8 degrees Celsius and a vapour pressure not exceeding 275 kilopascals absolute at 37.8 degrees Celsius;

"form" means the mould into which concrete or another material is to be placed;

"formwork" means a system of forms connected together;

"freeway" means a controlled-access highway that has a continuous dividing median and a normal posted speed limit of 90 kilometres per hour or more;

"full body harness" means a device that can arrest an accidental vertical or near vertical fall of a worker and which can guide and distribute the impact forces of the fall by means of leg and shoulder strap supports and an upper dorsal suspension assembly which, after the arrest, will not by itself permit the release or further lowering of the worker;

"generic installation drawing" means a drawing and related documentation, if any, that,

(a) identifies components, configurations and load limitations of a suspended work platform system or powered boatswain’s chair,

(b) is intended to be used at any location where all of the requirements in the drawing and documentation are satisfied, and

(c) bears the seal and signature of a professional engineer confirming that a suspended work platform system or boatswain’s chair installed in accordance with the drawing would be in compliance with the requirements of this Regulation;

"guardrail system" means an assembly of components joined together to provide a barrier to prevent a worker from falling from the edge of a surface;

"highway" means a common and public highway, street, avenue, parkway, driveway, square, place, bridge, viaduct or trestle, any part of which is intended for or used by the general public for the passage of vehicles;

"longitudinal buffer area" means the area of a project between the end of a lane closure taper and the start of a work area;

"magazine" means a place in which explosives are stored or kept, whether above or below ground;

"multi-point suspended scaffold" Repealed. [O. Reg. 242/16, s. 2];

"multi-point suspended work platform" means a suspended work platform more than 750 millimetres in width or a system of suspended work platforms in which any one platform is more than 750 millimetres in width that is supported from an overhead fixed support system by at least three primary load-carrying means of suspension to maintain the stability of the work platform or system of work platforms;

"non-destructive test" means one of the following methods of testing or examining a material, component or part to evaluate its condition without subjecting it to physical distortion, damage or destruction:

1. Eddy current testing.

2. Magnetic particle testing.

3. Liquid penetrant testing.

4. Radiographic testing.

5. Ultrasonic testing;

"professional engineer" means a person who is a professional engineer within the meaning of the Professional Engineers Act, 1984;

"public way" means a highway or other street, avenue, parkway, driveway, square, place, bridge, viaduct, or other open space to which the public has access, as of right or by expressed or implied invitation;

"rated platform capacity" means the combined weight of occupants, tools, equipment and other material that the manufacturer has indicated can be safely carried by a suspended work platform, work platform module or boatswain’s chair;

"roadway" means the travelled portion of a highway;

"rotary foundation drill rig" means a drill rig used for boring holes in soil for the placement of foundations or earth retention structures but does not include a drill rig that,

(a) is used for geotechnical sampling,

(b) is used for drilling water, oil or gas wells,

(c) is a rock drill or a diamond drill,

(d) is a digger derrick,

(e) is used for digging holes for posts, concrete forming tubes, poles or light standards,

(f) is a pile driver without an auger,

(g) is a horizontal boring machine, or

(h) is a tunnel boring machine;

"safety belt" means a belt worn around the waist of a worker and all the fittings for the belt appropriate for the use being made of it;

"safety factor" means the ratio of the failure load to the specified load or rated load;

"safety net" means a safety net that complies with section 26.8, and is located and supported in such a way that it arrests the fall of a worker who may fall into it without endangering the worker;

"service shaft" means a shaft by which people or materials are passed into or out of a tunnel under construction;

"shaft" means an excavation with a longitudinal axis at an angle greater than 45 degrees from the horizontal that is used to pass people or materials into or out of a tunnel or that used as an access to a boring or augering operation;

"sheathing" means the members of shoring that are placed up against the walls of an excavation to directly resist the pressure exerted from the walls of the excavation;

"sign truck"means a vehicle that has,

(a) four-way flashers and a mounted flashing arrowboard sign, or

(b) a portable trailer with a mounted flashing arrowboard sign;

"site-specific installation drawing" means a drawing and related documentation, if any, that identifies components, configurations and load limitations of a suspended work platform system or powered boatswain’s chair for use at a specific site;

"strut" means a transverse member of shoring that directly resists pressure from a wale;

"suitable", in relation to a procedure, material, device, object or thing, means sufficient to protect a worker from damage to the worker's body or health;

"suspended work platform system" means an access system comprising one or more overhead fixed supports, one or more suspension lines, hoisting devices, if any, and one or more work platforms that can be moved vertically, but it does not include a boatswain’s chair or a multi-point suspended work platform;

"tower crane" means a travelling, fixed or climbing mechanical device or structure that has,

(a) a boom, a jib or both,

(b) a power-driven drum and wire rope to raise, lower or move material, and

(c) a vertical mast;

"travel restraint system" means an assembly of components capable of restricting a worker's movement on a work surface and preventing the worker from reaching a location from which he or she could fall;

"traverse", when used in relation to a multi-point suspended work platform, means to move the platform horizontally, in a controlled manner, along the building or structure to which it is attached;

"trench" means an excavation where the excavation depth exceeds the excavation width;

"tunnel" means a subterranean passage into which a person may enter that is made by excavating beneath the overburden;

"underground", in relation to work, means inside a shaft, tunnel or caisson;

"vehicle" means a vehicle propelled by mechanical power and includes a trailer, a traction engine and a road-building machine;

"wale" means a longitudinal member of the shoring that is placed against the sheathing to directly resist the pressure from the sheathing; and

"work belt" means a belt that has a back support pad and a connecting hook at the front and that is capable of supporting a worker.

(1.1) Every non-destructive test required by this Regulation shall be carried out and interpreted by a person who has been certified by Natural Resources Canada to the appropriate level in accordance with CAN/CGSB Standard 48.9712-2014, Nondestructive Testing - Qualification and Certification of Personnel.

(2) In this Regulation, a short form listed in Column 1 of the Table to this subsection has the same meaning as the term set out opposite to it in Column 2.

TABLE

Item Column 1 Column 2
Short forms Corresponding terms
1. ANSI American National Standards Institute
2. CSA Canadian Standards Association
3. CAN National Standards of Canada

[O. Reg. 631/94, s. 1; 145/00, s. 1; 85/04, s. 1; 628/05, s. 1; 345/15, s. 1; 242/16, s. 1, 2; 142/17, s. 1]

Part II GENERAL CONSTRUCTION

Section 125

125. (1) Where work cannot be done on or from the ground or from a building or other permanent structure without hazard to workers, a worker shall be provided with a scaffold, a suspended work platform, a boatswain’s chair or a multipoint suspended work platform that meets the requirements of this Regulation.

(2) A worker who is on or under a scaffold, a suspended work platform system or a multi-point suspended work platform while it is being erected, altered or dismantled shall be on a part of the scaffold, suspended work platform system or multipoint suspended work platform that meets the requirements of this Regulation.

[O. Reg. 242/16, s. 9]

Scaffolds and Work Platforms

Section 136

136. (1) Cubes of masonry units on a scaffold platform shall be placed directly over the scaffold frame.

(2) If it is not practicable to comply with subsection (1), the masonry units shall be placed on the scaffold platform in a manner that conforms with the load capability provisions of the scaffold platform as set out in section 134.

(3) The surface of an outrigger bracket platform used by a masonry worker shall be not more than one metre below the associated material storage platform.

(4) Masonry units to be installed in a building or structure shall be distributed along the scaffold platform before being used.

Section 139

139. (1) An employer shall ensure that, prior to the first use of a suspended work platform system at a project, the entire system, including its suspension lines, has been inspected, tested and maintained in accordance with this Regulation, the manufacturer’s instructions, and clause 11 (Inspection and Testing) and Clause 12 (Maintenance) of CSA Standard Z271-10 .

(2) The employer shall ensure that the inspection, testing and maintenance referred to in subsection (1) is completed by,

(a) a competent worker; or

(b) if the CSA Standard Z271-10 requires the inspection or test be performed by a person with specific qualifications, such person.

[O. Reg. 85/04, s. 14; 242/16, s. 11]

Section 140

140. (1) An employer who uses a suspended work platform system shall ensure that there are permanent equipment logs respecting components of the suspended work platform system and that the logs,

(a) comply with clause 13 (Equipment Log) of CSA Standard Z271-10; and

(b) include a record of the inspections, tests, repairs, modifications and maintenance performed on the components.

(2) The employer shall make the permanent equipment logs available to an inspector on request.

[O. Reg. 242/16, s. 11]

Pre-Use Requirements: Fixed Supports, Roof Plans, Work Plans and Installation

Section 142

142. The employer shall ensure that the rated platform capacity of a suspended work platform, work platform module or boatswain’s chair is posted conspicuously on the suspended work platform, work platform module or boatswain’s chair, as the case may be.

[O. Reg. 242/16, s. 11]

Section 142.1

142.1 Sections 142.2 to 142.8 apply to every multi-point suspended work platform.

[O. Reg. 85/04, s. 15; 242/16, s. 1]

Section 142.2

142.2 (1) A multi-point suspended work platform and all its components shall be designed by a professional engineer in accordance with good engineering practice and with this section.

(2) A multi-point suspended work platform shall be designed to support, in addition to its dead load, live loads uniformly distributed over the platform surface of at least,

(a) 2.4 kilonewtons per square metre if the platform is to be used for masonry work;

(b) 3.6 kilonewtons per square metre if the platform is to be used for demolition work or for storage of masonry units or other related material or equipment; or

(c) 1.2 kilonewtons per square metre in any other case.

(3) In addition to the loads specified in subsection (2), a multi-point suspended work platform shall be able to support or resist,

(a) 1.1 kilonewtons concentrated on an area measuring 0.3 metres by 0.3 metres that is located on the platform at the position having the most adverse effect on the component under consideration;

(b) the wind load determined in accordance with the applicable provisions of the Building Code, based on a one in ten probability of being exceeded in any one year; and

(c) any other loads likely to be applied to it.

(4) The wind load referred to in clause (3)(b) may be reduced by 30 per cent if the professional engineer who designs the multi-point suspended work platform determines that it is appropriate to do so and indicates in writing that he or she has made the determination.

(5) Subject to clause (2) (c) and subsections (3) and (4), the professional engineer who designs the multi-point suspended work platform shall determine the minimum specified loads for erecting, dismantling, traversing or otherwise moving the multi-point suspended work platform.

(6) If a multi-point suspended work platform is to be used for abrasive blasting operations, there shall be an additional load allowance for the accumulation of grit on the platform to a depth of at least 25 millimetres.

(7) Subject to subsection (8), in designing a multi-point suspended work platform and its structural members, the following values of load factors, as described in the applicable provisions of the Building Code related to Limit States Design, shall be applied to the load requirements referred to in subsections (2) to (6):

1. Live load factor = 3.0.

2. Dead load factor = 1.5.

3. Wind load factor = 1.5.

(8) In designing the suspension and anchorage system of a multi-point suspended work platform,

(a) the value of the live load factor shall be 4.0;

(b) the value of the dead load factor shall be 2.0; and

(c) the value of the wind load factor shall be 2.0.

(9) Despite subsections (7) and (8), a multi-point suspended work platform and its components may be designed by working stress design if the safety factors for the multi-point suspended work platform and the structural members are at least equal to what would otherwise be provided under those subsections.

(10) Despite subsections (7) and (8), if the failure load of a component has been determined by testing, the minimum safety factors shall be,

(a) 3.0 for components of the multi-point suspended work platform;

(b) 4.0 for components of the suspension and anchorage system; and

(c) 10.0 for wire ropes, cables or chains used for hoisting, traversing or otherwise moving the multi-point suspended work platform.

(11) The failure load of a component referred to in subsection (10) shall be verified in writing by a professional engineer.

(12) A multi-point suspended work platform shall be designed, constructed and maintained in such a way that,

(a) the failure of one means of support or suspension will not cause any part of the platform to collapse or fail, under the most adverse loading condition as determined by the professional engineer who designs the multi-point suspended work platform; and

(b) compliance with subsections (7), (8), (9) and (10) is maintained in all fixed and moving conditions.

(13) The design of a multi-point suspended scaffold shall include adequate movement-limiting devices to be used when traversing or otherwise moving it.

(14) Before a multi-point suspended scaffold is erected, the constructor shall ensure that the professional engineer responsible for the structural integrity of the permanent building or structure from which the multi-point suspended work platform is suspended provides a written report approving the design loads imposed on the building or structure by the multi-point suspended work platform.

(15) Design drawings for a multi-point suspended scaffold shall include,

(a) a statement by the professional engineer that the design meets the requirements of this Regulation;

(b) the size and specifications of all components, including the type and grade of all materials to be used;

(c) the load factors and safety factors for the multi-point suspended work platform and all its components;

(d) all the specified loads, including the loads during erection, dismantling, traversing and otherwise moving; and

(e) the procedures for erection, dismantling, traversing and otherwise moving.

(16) The design drawings shall be followed, subject to subsection (17).

(17) A deviation from the design drawings is permitted if the deviation,

(a) is approved, in advance and in writing, by a professional engineer; and

(b) complies with this Regulation.

[O. Reg. 85/04, s. 15; 242/16, s. 1, 12; 142/17, s. 19]