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 https://www.osha.gov.

January 31, 1992

Mr. Daniel Zarletti
Director, Risk Management
Brand Scaffold Services, Inc.
1480 Renaissance Drive
Park Ridge, Illinois 60068

Dear Mr. Zarletti:

This is in response to your November 19 letter requesting the Occupational Safety and Health Administration (OSHA) to help you in your efforts to change the CAL-OSHA requirements for scaffold guardrail heights. I apologize for the delay in responding to your request.

When state plans are reviewed by Federal OSHA for adequacy, the criteria for acceptance is that the state provisions must be at least as effective as the federal provisions. Since federal standards are considered to be minimum standards, individual states have the option to implement more stringent standards if they wish. Although Mr. Barto's letter of 1979 is consistent with the American National Standards Institute requirements upon which the federal OSHA standards are based, there is no requirement that CAL-OSHA adopt the same position.

You may be interested to know that California has recently established an Advisory Committee to review the State's allowable tolerance for the height of guardrails. It is suggested that you continue to work with the State and, if possible, this Advisory Committee to address your concerns about the State's standard.

I wish you the best in your efforts.


Patricia K. Clark, Director
Directorate of Compliance Programs


November 18, 1991

H. Berrien Zettler
Deputy Director USDL - OSHA
Compliance Programs
200 Constitution Avenue, NW
Room N 3469
Washington, DC 20210

Dear Mr. Zettler:

This letter will confirm our phone conversation of 11/5/91 regarding my past correspondence with Patricia Clark on an interpretation of 1926.451(a)(5); scaffold handrail height. As you can see by the correspondence enclosed, my original request for an interpretation of this standard was on 6/18/91. Your response, dated 7/16/91 on behalf of Ms. Clark, interpreted this standard to permit a tolerance of plus or minus three (3) inches from 42" to the upper surface of the top rail (39 to 45 inches). The use of modular scaffold does not permit handrail heights within this range, therefore, Brand Scaffold Services was forced to engineer new designs in order to comply. Ms. Clark followed her correspondence with another letter on 10/9/91. That letter stated that her earlier interpretation was in error and correct interpretation was 36 to 45 inches. this corrected statement allows Brand Scaffold to comply to this standard under normal and/or usual applications. In an effort to achieve nationwide consistency, I have filed an August 1, 1991 petition to amend the CAL-OSHA handrail standard, Title 8 1644. Their current standard states the top rail height 'shall be 42-45"' above the working deck or platform with the midrail approximately halfway between them, with a one-inch plus or minus tolerance.

I have exhausted a study of data relative to fall accidents dating back to 1970 which shows only credible experience when the fall occurred when no railings were present. There is essentially no experience suggesting the '36-45" safety range' was unsafe or provided insufficient protection from falling off a walking deck.

The International Labor Union in Geneva, Switzerland has been keeping similar records for forty-four (44) years in a work environment where modular scaffolding was originally designed with the exact same results.

CAL-OSHA records have concluded no major accident experience from falls while the top rail height was maintained at their required 42-45" levels. Therefore, it is clear that the 40 plus years of international experience, 20 plus years of Federal OSHA and 20 plus years of CAL-OSHA experience has provided us with a safe "range" for handrail heights (36-45"), thus extending the CAL-OSHA tolerance using this viable evidence.

The interpretation error has cost Brand Scaffold significant inconvenience and expense. I would ask for your support through Ms. Clark's authority by:

* Personal endorsement for nationwide consistency

* Accident data supporting 36-45" handrail height since adoption

* Future plans to incorporate standards specifically designed for modular systems scaffolding.

Mr. Zettler, as with any legislation change, efficiency, support and accuracy are imperative.

Thank you for your willingness to contribute.


Daniel Zarletti
Director - Risk Management

July 16, 1991

Mr. Daniel Zarletti
Director, Risk Management
Brand Scaffold Services, Inc.
1480 Renaissance Drive
Park Ridge, Illinois 60068

Dear Mr. Zarletti:

Thank you for your letter of June 18, concerning the allowable tolerance for the height of guardrails as specified at 29 CFR 1926.451(a)(5).

The Occupational Safety and Health Administration (OSHA) standard at 29 CFR 1926.451(a)(5), states that, "Guardrails shall be 2 x 4 inches or the equivalent, approximately 42 inches high, with a midrail, when required. ..." As you are aware, the standard does not identify the acceptable tolerance for the height of the top rail.

OSHA permits a tolerance of plus or minus 3 inches for the location of the upper surface of the top rail. Therefore, the upper surface of the top rail may be located at any point between 39 and 45 inches above the floor, platform, or working surface. However, it should be noted that the upper surface of the top rail of a guardrail system must not deflect below 39 inches from the floor when placed under a downward load of 200 pounds as required by 29 CFR 1926.500(f)(1)(iv), copy enclosed.

This interpretation applies to all guardrail systems used at construction sites.

In response to your request for other interpretations relevant to 1926.451, we enclose the following OSHA Instructions:

1. OSHA Instruction STD 3-10.1B, August 14, 1972.
2. OSHA Instruction STD 3-10.2, October 30, 1978.
3. OSHA Instruction STD 3-10.3, October 30, 1978.
4. OSHA Instruction STD 3-10.4, October 30, 1978.

If we may be of further assistance, please contact us.


Patricia K. Clark, Director
Directorate of Compliance Programs


June 18, 1991

Patricia K. Clark
Director - Compliance Programs
200 Constitution Avenue N.W.
Room N. 3469
Washington D.C. 20210

Dear Ms. Clark:

I respectfully request your interpretation of OSHA Standard 1926.451(a)(5). The use of the word "appropriately" has sustained a debate on just how much tolerance is allowed, plus or minus the stated 42".

Please include any and all other interpretations relevant to 1926.451.

Thank you very much for your assistance.

Best personal regards,

Daniel Zarletti
Director - Risk Management

March 14, 1979

Mr. George E. Payne
Vice President
Kwikform America, Inc.
19781 Mitchell Drive
P.O. Box 17387
Irvine, California 92714

Dear Mr. Payne:

This is in response to your recent letter concerning the conflict that exists between OSHA regulations impacting the scaffold industry.

The Occupational Safety and Health Administration's regulations for scaffold guardrails do require height requirements as indicated in your letter. However, during normal routine operations in the various industries (construction, general industry and maritime) guardrails 36 inches to 42 inches in height would satisfy the intent of the standard. The deviation from the specific requirements as indicated above would have no direct or immediate relationship to safety and health and would not be required to be abated.

I have enclosed for your information a copy of OSHA Program Directive #200-67 (Revision #1). If I may be of further assistance, please contact me.


John K. Barto, Chief
Division of Occupational Safety Programming