Inspecting Tube and Coupler Scaffolds
Bearers
Bearers (also called transoms) are horizontal transverse scaffold members (which may be supported by runners) upon which the scaffold platform rests and which joins scaffold uprights, posts, poles, and similar members.
- Bearers should be installed transversely between the posts, and when coupled to the posts, the inboard coupler should bear directly on the runner coupler.
- When the bearers are coupled to the runners, the couplers should be as close to the posts as possible.
- Bearers should extend beyond the posts and runners and provide full contact with the coupler.
- Verify that when platforms are being moved to the next level, the existing platform is left undisturbed until new bearers have been set in place and braced prior to receiving the new platforms.
Runners
Runners (also called ledgers) are the lengthwise horizontal spacing or bracing members which may support the bearers.
- The scaffold should have runners installed along its entire length and along both the inside and outside posts at the various level heights.
- Runners should be interlocked on straight runs to create continuous lengths and be coupled to each post.
- Bottom runners should be located as close to the base as possible. Couplers should be made of structural metal.
Real-Life Example
Improper Coupling Results in Two Deaths
A tubular, welded-frame scaffold, 31 feet high, was erected to paint a 33-foot high sign at the entrance of a new shopping mall. After the sign had been partially painted, the scaffold was moved to allow concrete to be placed around the sign. Several days later, a crew of seven workers was instructed to replace the scaffold and finish painting the sign. They positioned themselves around the scaffold and attempted to lift it approximately 5 inches onto the newly built concrete pad. As they were lifting the scaffold, the top section partially separated from the adjoining section, toppled over, and contacted a power line. A 28-year old carpenter and a 31-year old laborer were electrocuted. The other five workers were hospitalized with electrical burns.
Knowledge Check Choose the best answer for the question.
3-2. The lengthwise horizontal spacing or bracing members of a tube and coupler scaffold are called _____.
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