Types of Scaffolding
A scaffold can be generally defined as a temporary structure supporting a platform positioned at an elevation above the ground. Its purpose to provide a working surface to support workers and their necessary tools and material.
A scaffold must have at least one platform and can be supported from the ground or suspended from overhead supports.
A system scaffolding structure is essentially a frame structure utilizing a specialized modular connection and has evolved from the general principles of tube and clamp scaffolding The major difference between tube and clamp scaffolds and system scaffolds is the connection of the uprights -“standard”- to the horizontal members -“transoms and ledgers”- and the diagonal members -“braces”-
The connection between the transoms and ledgers and the standards is normally by a specially designed mouth piece and rosette device or by other modular connection methods. The connection device is also used for the connection of the various diagonal members or braces.
Tubular metal frame scaffolding systems are probably one of the most commonly used scaffold system in the construction industry. The scaffold consists of welded steel or aluminum frames connected by cross braces to orm a framework to support scaffold planks or other scaffold platform systems.
Frames are manufactured in a wide variety of sizes and configurations, the most common being a standard 5 foot by 5 foot frame and walk-through arch or arch frame
The arch frame scaffold is very common in the masonry construction sector as it allows convenient movement between the frames for distribution of materials. Outrigger brackets or side brackets can be installed on the side of the scaffold at varying levels to provide a convenient personnel platform for work at the building face.
A swingstage could be described as a suspended platform varying in sizes from 5 feet to 32 feet in length that is suspended from permanent or temporary rigging on the roof of a high rise building. Fixed length platforms vary in sizes up to 32’ in length and typically have a capacity of 750 lbs. In recent years, Modular Platform have become very popular, allowing for increased flexibility and easier storage for both the end user and supplier. Modular Platforms come in various size components that allow for increased stage lengths greater than 32 feet. Depending on the length of the stage and manufacturer, Modular Platforms can have capacities as high as 1500 lbs.
Both styles of platforms can have manual, air or electric lifting devises to allow for a platform to be elevated or lowered up the sides of buildings, stacks, boilers or any other elevated structure.
Swingstages are typically used by: window washers, restoration contractors, window installers, caulking contractors or any other trade where high rise access is required.
The first portable scissor type platform was developed in the early 1800’s as a method of spotting artillery hits and enemy positions. This towable devise was brought by horses into the field and elevated and lowered by a manual crank. Internal combustion engines were added in the 1930’s and battery power became a standard in the 1960’s.
The first boom type platforms were developed for the agricultural market, hence the term cherry picker.
From these beginnings the boom type and scissor type powered elevating work platforms have virtually become a tool of the trade on construction sites in North America. Tens of thousands of these devices ranging in heights from 15 feet to 150 feet are employed in Industrial and Construction environments every day.
These devises are regulated, in Canada, by the CSA B354 family of standards. These standards cover material, manufacture, and test criteria, as well as maintenance and operator training requirements.
Fall protection is, by far, the greatest safety challenge for erectors and all types of scaffolding and access systems. Over 70% of all scaffold related fatalities are falls from the platform or access. In addition, the use of most personal fall arrest systems (PFAs) for scaffolding represents even greater challenges. PFAs used on scaffold and access devices must contend with difficult issues such as: anchorage, freefall, swingfall, energy absorption, obstructions and impalement hazards.
Guardrails are by far the most common and effective fall protection tool for supported scaffolds, however, they are not an easy solution for scaffolds while being erected or dismantled or even for other access systems such as: swingstage scaffolds and powered elevating work platforms.
The SIAC Fall Protection Committee is dedicated to working with the SIAC member firms and affiliates, such as regulatory and standards agencies as well as fall protection equipment manufacturers to develop and communicate fall protection “industry best practices” for scaffolds and access systems.
The provision of powered access to a system of scaffolding by means of a platform fixed to a vertical mast attached to the side of the building under construction or maintenance.
Shoring is the process of supporting a building, vessel, structure, or trench with shores (props) when in danger of collapse or during repairs or alterations. Shoring comes from shore a timber or metal prop. Shoring may be vertical, angled, or horizontal.