OSHA Regulations on Scaffolding

In the United States, construction safety regulations are developed by the Occupational Safety and Health Administration (OSHA). OSHA Standard 1926 describes the various safety measures that should be taken on construction sites, where workers face dangers from a variety of factors, including falling objects, equipment, tools and exposure to hazardous materials. Subpart L of this Standard regulates the use of scaffolds, which are portable devices used to allow workers to perform tasks above ground level. Scaffolds pose a danger to both the employees working on them and people at ground level. To minimize risks, scaffold users must follow strict standards, including those related to design, training and safe operations.

Load Capacity

According to Subpart L, scaffolds must be designed to support the weight of the scaffold itself, as well as four times the intended load, for both employees and materials. All connections to the roof or building structure must be capable of resisting four times the tipping momentum of a fully loaded scaffold. On suspended systems, all ropes must be capable of supporting six times the rated load of the system.

Design

Each deck or platform on a scaffold must be placed no more than 1 inch apart, and no further than 1 inch from any support structures. In cases where this is not possible due to obstruction, a maximum space of 9½ inches is permissible between planks and support beams. All decks must be at least 18 inches wide, while ladder jacks and roof brackets must be at least 12 inches wide. In spaces where these minimum widths cannot be met, protective guardrails must be placed around the deck.

Supported Scaffolds

All non-suspended scaffolds with a height-to-base-width ratio greater than 4 to 1 must be braced or supported to prevent tipping. Ties and braces must be installed at both ends of a scaffolding system, and also at intervals of every 30 feet horizontally. A system of bracing must be used on any size ratio system when the scaffold will be subjected to unequal side loads, such as cantilevered platforms. All vertical members on supported scaffolds must be set onto stable base plates and must not be placed on loose objects or on mechanical equipment.

Suspended Systems

All suspended scaffolding systems must be designed by an engineer who is experienced in this type of structural design. The system should be installed by a competent person and inspected before each use. Only items designed as counterweights may be used for this purpose, and must be secured mechanically to the scaffolding system. All support items such as hooks, roof irons and parapet clamps must be made of steel or iron and supported by tiebacks that have the same strength as the scaffold's ropes. No gas-powered hoists of lift systems may be used on suspended scaffolds.

Safe Installation and Use

All scaffolding systems must be installed and maintained by employees who have been specifically trained for this task. No employees may erect or work on scaffolding systems that are covered with ice, snow or any other slippery substance. Working during high winds is only permissible if employees wear personal-fall-protection systems and are protected by suitable wind screens. Temporary devices such as boxes or chairs may not be placed on the scaffold to allow workers to reach higher heights. All employees working more than 10 feet above the ground must be protected from falls using a system of guardrails or a protective harness. A system of canopies, toe boards and guardrails may be used to protect people walking below. Typically, these protective systems are regulated by individual counties and states and are designed during the permit process with help from local officials.