Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at

July 23, 1998

Mr. Gene Follstaedt
American Schack Company, Inc.
P.O. Box 1395
Wexford, PA 15090-1395

Dear Mr. Follstaedt:

Thank you for your letter of June 24, concerning the Occupational Safety and Health Administration's (OSHA) standard 29 CFR 1910.27. Your letter stated two questions and provided a sketch of a product American Schack manufactures. Your questions are:



  1. Is this American Schack Company, Inc. steel stack to be considered a chimney?
  2. Are platform spacings that exceed 30'-0" in compliance with OSHA regulations?

Reply to question 1: As a flue device, your company's steel stack would be considered to be a chimney within the context of the 1910.27 standard where it addresses chimney ladders.

Reply to question 2: The current OSHA standard 1910.27(d)(2) establishes a maximum limit of 30 feet between platforms, so ladder distances in excess of 30 feet without an intermittent platform would not be in compliance with the standard.

This standard was part of the initial package of standards promulgated in 1971. Since then the reference standard for 1910.27, American National Standards Institute (ANSI) standard ANSI A14.3,has undergone several modifications. Also, OSHA published a notice of proposed rulemaking in April 1990 to modify and update 1910.27. Both of these documents contain provisions extending the distance of continuous climb on a ladder with a cage or well to a length not to exceed 50 feet.

OSHA's de minimis policy would apply to an employer who complies with a proposed standard or amendment, such as the April 1990 proposed rulemaking, or a consensus standard, such as ANSI, rather than with the standard in effect at the time of inspection and the employer's action clearly provides equal or greater employee protection. The de minimis policy states that violations of a standard which have no direct or immediate relationship to safety or health and will not be included in citations. Thus, the caged ladders on the stack which exceed 30 feet are technically in violation, however, since they comply with both the OSHA proposed rule and the current consensus standard for fixed industrial ladders and the level of safety is not diminished, they will not be cited.

If you have further questions concerning this letter please contact [the Office of General Industry Enforcement at (202) 693-1850].


John B. Miles, Director
[Directorate of Enforcement Programs]

[Corrected 4/4/2005.

Note: On April 10, 1990 OSHA published proposed revisions to Walking and Working Surfaces; Personal Protective Equipment (Fall Protection Systems); Notices of Proposed Rulemaking; Slips; Falls; Trips in Federal Register 55:13360-13441. It is available electronically only as an abstract. On May 2, 2003 OSHA reopened the rulemaking record on the proposed revisions to Walking and Working Surfaces and Personal Protective Equipment (Fall Protection Systems). It was re-published in its entirety in Federal Register 68:23527-23568 and is available electronically.]

June 24, 1998

Mr. Gene Follstaedt
American Schack Company, Inc.
P.O. Box 1395
Wexford, PA 15090-1395

SUBJECT: Ladder/Landing Platform Requirements

Dear Mr. Syzmanski:

In follow to our telephone conversation of June 11, 1998, please be advised that we need your help in obtaining clarification concerning an OSHA compliance issue. Our company, American Schack Company, Inc., has sold/designed/fabricated a vertically fired, cyclonic type thermal oxidizer with a refractory lined steel stack mounted directly on top of it. The thermal oxidizer section is 41'-0" high and the refractory lined steel stack section is 150'-6" high. The entire structure, which sits on 8'-0" high concrete pedestals, stands 199'-6" in height. Please refer to the enclosed drawing for reference.

The ladder/landing platform design we have provided incorporates fixed caged ladders with platforms spaced as follows:





  Ground to landing platform #1 27'-3"
Landing platform# 1 to platform #2 27'-3"
Platform #2 to landing platform #3 32'-6"
Landing platform #3 to landing platform #4 32'-6"
Landing platform #4 to platform #5 32'-6"
Platform #5 to platform #6 39'-6"


Each ladder section is offset with regards to adjacent ladder sections.

Our client, Continental Carbon Company, Phenix City, Alabama, has concerns that our design may not be in compliance with OSHA Regulations (Standards - 29 CFR), Standard Number: 1910-27, Standard Title: Fixed Ladders, SubPart Number: D, SubPart Title: Walking-Working Surfaces, para. (d)(2) "Landing Platforms", which reads as follows: "When ladders are used to ascend to heights exceeding 20 feet (except on chimneys), landing platforms shall be provided for each 30 feet of height or fraction thereof, except that, where no cage, well, or ladder safety device is provided, landing platforms shall be provided for each 20 feet of height or fraction thereof. Each ladder section shall be offset from adjacent sections. Where installation conditions (even for a short unbroken length) require that adjacent sections be offset, landing platforms shall be provided at each offset."

Continental Carbon Company's concerns are twofold:






  1. Is this American Schack Company, Inc. steel stack to be considered a chimney?
  2. Are platform spacings that exceed 30'-0" in compliance with OSHA regulations?

In designing the ladders and landing platforms, American Schack Co., Inc. (ASC) referenced ASME, STS-l-1992 (Revision Of ASME/ANSI STS-1-1986), "Steel Stacks", An American National Standard. This standard clearly states in its introduction that "It (this Standard) gives the requirements for climbing and access based upon current Occupational Safety and Health administration (OSHA) standards. Para. 6.3.8, Landing Platforms, states "When ladders are used to ascend to heights exceeding 50 ft (except as provided in para. 6.3.1 ), platforms shall be evenly spared at intervals of 50 ft or less.". Para. 6.3.10, Safety Cages and Wells, states "Except as provided in para. 6.3.11, safety cages or wells shall be provided for ladders of more than 20 ft to a maximum of 50 ft. (See para. 6.3.8.)" Para 6.3.11, Climbing Protection Devices, referenced in both statements above, merely states that "Climbing protection devices may be used on ladders over 20 ft in unbroken length in lieu of cage protection."

Secondly, the ASC design referenced ANSI Standard A14.3-1992. Para. 4.1.3 states "A cage, well or ladder safety system shall be provided where a single length of climb is greater than 24 feet but does not exceed 50 feet.". Para. states "Where cages or wells are used: (1) The ladder shall consist of multiple sections. (2) Each section shall be horizontally offset from adjacent sections. (3) A landing platform shall be provided at least every 50 feet within the length of climb.

We have been advised by several prominent chimney/steel stack design companies/consultants that OSHA adopts ANSI A14.3 and ASME STS-1-1992 as their governing guides since OSHA Part 1910.27 takes exception to chimneys. In these regards, ASC feels we are in compliance with OSHA Regulations.

Lastly, we would appreciate if you could expedite a response as quickly as possible since the unit is currently being erected at the job site and a problem with our design will incur serious penalties to both ASC and our client in time and money.

With kindest regards,

Gene P. Follstaedt
Project Manager