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Frame or Fabricated Scaffold
Mobile Scaffold
Pump Jack Scaffold
Ladder Jack Scaffold
Tube and Coupler Scaffold
Pole Scaffold
Specialty Scaffold |
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U.S. Department of Labor
Occupational Safety & Health Administration
www.OSHA.gov
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Tube and Coupler Scaffold
 Tube
and coupler scaffolds are so-named because they are built from tubing connected by coupling devices. Due to their
strength, they are frequently used where heavy loads need to be carried, or where multiple platforms must reach several
stories high. Their versatility, which enables them to be assembled in multiple directions in a variety of settings,
also makes them hard to build correctly.
Note: The requirements on this page are specific to
tube and coupler scaffolds only. For requirements that apply to all types of supported scaffolds, please refer to the
Frame or Fabricated module of this eTool.
| << General
Requirements |
- When platforms are being moved to the next level, the existing platform must be left
undisturbed until the new bearers have been:
- Set in place, and
- Braced before receiving the new platform. [1926.452(b)(1)]
- Couplers must be made of a structural metal, such as:
- Drop-forged steel,
- Malleable iron, or
- Structural-grade aluminum. [1926.452(b)(9)]
- The use of couplers made from gray cast iron is prohibited. [1926.452(b)(9)]
- Tube and coupler scaffolds over 125 feet in height must be:
- Designed by a registered professional engineer, and
- Constructed and loaded in accordance with that design. [1926.452(b)(10)]
See
Appendix A for non-mandatory examples of design and
loading criteria.
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| << Bracing |
-
Transverse bracing forming an "X" across the width of the scaffold must be installed
at the scaffold ends, and at least at:
- Every third set of posts horizontally (measured from only one end), and
- Every fourth runner vertically. [1926.452(b)(2)]
- Bracing must extend upward diagonally to opposite sides of the scaffold, such as from the
inner posts or runners to the next outer posts or runners, or vice versa (see diagram). [create
diagram] [1926.452(b)(2)]
- Building ties must:
- Be installed at the bearer levels between the transverse bracing, and
- Meet the requirements of 1926.451(c)(1). [1926.452(b)(2)]
- On straight run scaffolds,
longitudinal bracing across the inner and outer rows of posts must:
- Be installed diagonally in both directions, and
- Extend upward from the base of the end posts to the top of the scaffold at approximately a
45-degree angle. [1926.452(b)(3)]
- On scaffolds whose length is greater than their height, longitudinal bracing must be repeated
beginning at least at every fifth post. [1926.452(b)(3)]
- On scaffolds whose length is less than their height, longitudinal bracing must be installed from the base
of the end posts upward to the opposite end posts, and then in alternating directions
until reaching the top of the scaffold (see diagram). [create diagram] [1926.452)(b)(3)]
- Bracing must be installed as close as possible to the intersection of the bearer and post
or runner and post. [1926.452(b)(3)].
- Where conditions do not permit the attachment of bracing to posts, bracing must be
attached to the runners as close to the post as possible. [1926.452(b)(4)]
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| << Bearers |
- Bearers must be installed transversely between posts. [1926.452(b)(5)]
- When bearers are coupled to posts, the inboard coupler must:
- Bear directly on the runner coupler, and
- Be as close to the posts as possible. [1926.452(b)(5)]
- Bearers must extend beyond the posts and runners, and provide full contact
with the coupler. [1926.452(b)(6)]
- The bottom bearers must be located as close to the base as possible. [1926.452(b)(8)]
|
| << Runners |
- Runners must be installed along the length of the scaffold, located at level
heights on both the inside and outside posts. [1926.452(b)(7)]
- On outside posts, tube and coupler guardrails and midrails may be used in
lieu of outside runners. [1926.452(b)(7)]
- Runners on straight runs must be:
- Interlocked to form continuous lengths, and
- Coupled to each post. [1926.452(b)(8)]
- The bottom runners must be located as close to the base as possible. [1926.452(b)(8)]
|
| << Non-mandatory
Guidelines |
Minimum Size of Members
1926
Subpart L Appendix A (2)(b)
| |
Light Duty |
Medium Duty |
Heavy Duty |
| Maximum Intended Load |
25 pounds/foot˛ |
50 pounds/foot˛ |
75 pounds/foot˛ |
Posts, runners, and braces
NOTE: Longitudinal diagonal bracing must be installed at an angle of 45° (±5°). |
Nominal 2 inches (1.9 inches) OD steel tube or pipe |
Nominal 2 inches (1.9 inches) OD steel tube or pipe |
Nominal 2 inches (1.9 inches) OD steel tube or pipe |
Bearers
NOTE: Bearers must be installed in the direction of the shorter dimension. |
Nominal 2 inches (1.9 inches) OD steel tube or pipe and a maximum
post spacing of 4 feet x 10 feet |
Nominal 2 inches (1.9 inches) OD steel tube or pipe and a maximum post spacing
of 4 feet x 7 feet
Nominal 2˝ inches (2.375 inches) OD steel tube or pipe and a maximum post spacing of 6 feet x 8 feet. |
Nominal 2˝ inches (2.375 inches) OD steel tube or pipe and a
maximum post spacing of 6 feet x 6 feet |
| Maximum runner spacing vertically |
6 feet 6 inches |
6 feet 6 inches |
6 feet 6 inches |
Maximum Number of Planked Levels
1926
Subpart L Appendix A (2)(b)
| Maximum Number of Additional Planked Levels |
| |
Light Duty |
Medium Duty |
Heavy Duty |
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| Number of Working Levels |
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Maximum Height of Scaffold |
| 1 |
16 |
11 |
6 |
125 feet |
| 2 |
11 |
1 |
0 |
125 feet |
| 3 |
6 |
0 |
0 |
125 feet |
| 4 |
1 |
0 |
0 |
125 feet |
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