guardrail requirements osha. This 28-page document covers the basics of fall protection systems, equipment, and regulations, as well as practical tips and examples for different work scenarios. guardrail requirements osha

 
 This 28-page document covers the basics of fall protection systems, equipment, and regulations, as well as practical tips and examples for different work scenariosguardrail requirements osha 8 m) or more above a lower level shall be protected from falling by the use of guardrail systems,

Spiral stairs must meet the vertical clearance requirements. Never walk. With both standards, OSHA deems guardrail compliant under the following conditions: Vertical height of 42 inches. Guardrail systems and their use shall comply with the following provisions: 1926. OSHA published a final rule on walking-working surfaces and personal protective equipment in November 2016 that updated requirements for slip, trip and fall hazards. 1926. (link is external) Summary Report of 2021 MASH Virtual Roundtables. not specified. 23 (a) (2) Designed into or is an integral part of machines or equipment. The Ontario Building Code | Handrails 3. 2. Specifically, we will consider the use of certain physical barriers that fail to meet the criteria for a. Private stairways 30 inches (762) or less in height may have a handrail on one side only. More information about the OSHA Standards and agricultural safety is available at the following Web sites:1926. 29 (f) (1) (iii) (A)) Platform Guardrail Height: The top edge of the top guardrail must be 42 inches, plus or minus 3 inches, above the. In addition to paragraph (b) of this section, the employer must ensure standard stairs: ( 1) Are installed at angles between 30 to 50 degrees from the horizontal; ( 2) Have a maximum riser height of 9. Addressing OSHA dock safety can be a tricky thing. Minimum 6′-8″ headroom height clearance for stairway. So, that height can be anywhere from 39 inches to 45 inches. State Plan Standards. Department of Labor, OSHA, Office of Construction Standards and Guidance, Room N3468, 200 Constitution Avenue, N. Whenever guardrail systems are used, they must meet the definition of a "guardrail system" in §1926. 23(c)(1), the open sides of platforms more than four feet above an adjacent floor or ground level must be guarded by a standard railing or the equivalent. The guidelines for these aspects of mezzanine railing include: In-fill mid-rails or panels need to be installed to keep the opening from being more than 19 inches. Refer to Plan Insert Sheets (GR series) and the July 2012 Version of this Manual for Type 5 guardrail design standards. Federal OSHA: requires a 200 pound point load. 1910. A stair rail or stair guard is a safety railing or barrier located along the open side(s) of a stairway. However, we believe that there are recognized hazards associated with openings in roofs. Department of Labor, Occupational Safety and Health Administration (OSHA) under the general industry standard 29 CFR 1910. Note that our enforcement. Passive fall protection protects many vulnerable areas and provides safety for all people, not just active employees on a job site. Any working surface 4 feet or higher must be protected with guardrails on all sides at least 42" tall and have to withstand 200 pounds of force. Mid rail height of 21 inches. On outside plaza, patio, and garden areas, alternate means of protection are acceptable if the same degree of safety is provided. Stair Rails and Handrails. Guardrail Requirements vs. It applies to classrooms with permanent and temporary floor holes and openings greater than 1 inch in its least dimension, floor drains, manholes, hatchways, ladder. 452(w)(6)(ii)). 23 (a) (4), therefore, requires that skylights in the roof of buildings through which persons may fall while walking or working shall be guarded by a standard. Here is a summary to make it easy for you: The top rail must be 42 inches in height, give or take 3 inches. The roadway may be abutted by steep. In these situations, OSHA believes guardrail systems offer the appropriate level of fall protection and the record supports this conclusion. Top rail must withstand 200 lbs load in any direction. 1053 (a) (4) (i) The minimum clear distance between the sides of individual-rung/step ladders and the minimum clear distance between the side rails of other fixed ladders shall be 16 inches (41 cm). DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT Page 5 of 14 DEFICIENCY 2 – UNIT: HANDRAIL IS NOT SECURE. This includes the top of retaining walls over 4 feet in height. 502(d) and the requirements of the scaffold standard are met. §3214. Do the OSHA Construction standards apply to me? The standards apply to: All contractors who enter into contracts which are for construction, alteration, and/or repair, including painting and decorating. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. 502(b)(9) states that top rails and mid rails must have a thickness or nominal diameter of at least ¼ of an inch to. If the employer chooses to use a guardrail system, he must comply with the following provisions: Top edge height of top rails, or equivalent guardrail system members, must be between 39 and 45 inches above the. Access to wing walls from floors of dry docks shall be by ramps, permanent stairways or ladders meeting the applicable requirements of § 1915. 1926. 10. 1917. 62 cm). 1926. gov. 4. Here are some highlights: Do not turn on an incline. Training and qualification of each roadway worker in on-track safety for operators of roadway maintenance machines. 1 m) plus or minus 3 inches (8 cm) above the walking/working level. OSHA stair requirements suggest that: 1910. Railing height for guard rail. The OSHA requirements state that guardrails should be able to resist at least 200 pounds of pressure applied directly to the. Field Information Memorandum #75-40, June 2, 1975, Subject: Guarding Floor and Wall Openings and Holes - General Industry (copy enclosed) covers situations where. 1-2007, Safety Requirements for Workplace Walking/Working Surfaces and Their Access; Workplace Floor, Wall and Roof Openings; Stairs and Guardrail Systems. safety monitoring systems. 29(b) and its subparts. e. OSHA published a final rule on walking-working surfaces and personal protective equipment in November 2016 that updated requirements for slip, trip, and fall hazards. Guardrail systems must be capable of withstanding, without failure, a force of at least 200 pounds applied in a downward or outward direction at any point within two inches of the. the system meets the guardrail. 1926. 1915. RE: New OSHA Handrail Requirements cadred (Structural) 19 Jun 17 20:15 It does say you can go to 38" now from the leading edge of the tread to the top surface of the rail if combining the guardrail with handrail (dual purpose). OSHA gives you some flexibility on this. OSHA standard 1926. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. The OSHA non-mandatory guidelines do not provide suggested hardware for fastening the guardrails to the ground. Minimum tread depth of 9. Now, if your loading dock is at 46”, per OSHA dock safety standards, fall protection is not required. Handrail height of alternating tread devices and ships ladders, measured above tread nosings, shall be uniform, not less than 30 inches (762 mm) and not more. All workers reaching more than 10 inches below the level of the walking or working surface on which they are working must be protected by a guardrail system, safety net system, or personalOn November 18, 2016, OSHA published a final rule on Walking-Working Surfaces and Personal Protective Equipment (Fall Protection Systems) in the Federal Register ( 81 FR 82494 ). 25 inches in diameter or 0. The retaining wall or retaining wall system is located closer than 2 feet to a walk, path, residential yard, public common area, parking lot or driveway. ft. 4. 28; 1910. 1052(c)(6) and 1926. OSHA Guardrail Load Requirements. 29(b) and its subparts. These letters provide guidance to clarify the application of an established OSHA standard, policy, or. Our portable guard railing is 42 inches tall. This regulation states that, “Guardrail systems. 34″ and 42″. In addition, if the guardrail has intermediate vertical members (uprights between the top and bottom rails), the gaps should be no more than 19 inches (see 1910. Will the Guardrail Meet Loading Dock Railing Requirements? OSHA details the requirements for guardrails in more detail since the 2017 update. 1926. The job-built guardrail systems were evaluated to determine whether they complied with OSHA regulation 29 CFR 1926. 23(e)(6) states: "All handrails and railings shall be provided with a clearance of not less than 3 inches between the handrail or. According to OSHA, the top edge height of top rails (or equivalent guardrail system members) must be 42 inches (107 cm), plus or minus 3 inches (8 cm), above the walking-working surface. The agency’s standard on walking-working surfaces for general industry (1910 Subpart D) was developed to help prevent dangerous falls from height or slips and trips on the same level (working surface). Figure D-11-- Guard Rail Systems. Phone: Fax: Buy guardrail netting for mid-rail and toe board fall protection, in addition to overhead protection against debris. 501(b)(1), even where there is a permanent guardrail with a 36-inch top rail that, pursuant to STD 01-01-010, is acceptable for. Toeboards need to be around 3. 502 (b) (3), (4), and (5). The fall protection requirements for residential construction are set out in Subpart M at 29 CFR 1926. C. 25 (b) (2) Vertical clearance above any stair tread to any overhead obstruction is at least 6 feet, 8 inches (203 cm), as measured from the leading edge of the tread. ”. . (1. The employer must ensure guardrail systems meet the following requirements: 1910. 1926. Section 1910. it's vital that your devices meet all the standards set forth by OSHA and that your workers are trained on their proper use. Scaffolding. 21 - Scope and definitions. The requirements are divided into 3 sections for guardrails, which are. 501(b)(13), workers engaged in residential construction six (6) feet or more above lower levels must be protected by conventional fall protection (i. In addition, OSHA also issued an interpretation (55 FR 13407; April. 26 (a) Dockboards are capable of supporting the maximum intended load in accordance with § 1910. The agency has received numerous questions asking when handrails are required, and about the height requirements for handrails on stairs and stair rail systems. OSHA guidelines on guardrail fall protection criteria dictate that a guardrail safety system’s top edge must be 42(±)3 inches above the floor. When assessing an employer's compliance efforts, the Agency considers the requirements of pertinent. OSHA scaffolding standards are at 29 Code of Federal Regulations 1926. Details are at GUARDRAIL CODES & STANDARDS - this article. [29 CFR 1926. 760 (c) (2) Access to a CDZ shall be limited to only those employees engaged in leading edge work. 5 inches (24 cm); ( 3) Have a minimum tread depth of 9. Handrail safety is just as important as the safety of the staircase itself. GUARDRAIL 101. 6) (1926. 5". 1926. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. Guardrail systems 1910. W. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. You’re completely OSHA compliant for inspection at a moments notice. Therefore let us recap on the residential stair code requirements: Minimum 36 inch clear width for stairway. 4. 71 (j) (1) and (2), unless the nature of the work in progress or the physical conditions prohibit the use. Employers should train workers to: Check to see that a guardrail system is in place before working on the scissor lift. 1052(c)(6) and 1926. Their standard states, "A standard guardrail shall consist of top rail, midrail or equivalent protection, and posts, and shall have a vertical height within the range of 42 inches. The modular system allows for the guardrail to be customized to best fit all the angles and elevations of your rooftop. 1910. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. Stairways less than 44 inches (1118 mm) in width or stairways serving one individual dwelling unit in Group R, Division 1 or 3 Occupancy or a Group R, Division 3 congregate residence may have one handrail. . Handrail height, spacing, and incline are all addressed by the International Residential Code (IRC) and the International Building. 1-2007, Safety. 1926. Maximum 4-1/2 inch handrail projection into stairway width, on either side. 1915. California Code of Regulations, Title 8, Section 3214. 13(c)] The use of wire ropes as top rails and intermediate rails of guardrail systems used for perimeter protection or for guardrails used on scaffolding meeting the equivalent requirements of 29 CFR 1926. 452, . Dear. 454. Maximum mesh size must not exceed 6 inches by 6 inches. The newest OSHA revisions include the following criteria for OSHA 1910. ( 4) Have a minimum width of 22 inches (56 cm) between vertical. If you have an edge that does not pose this risk, you should be OK with standard railing without toeboard. 48 (b). Maximum 4-1/2 inch handrail projection into stairway width, on either side. The top edge height may exceed 45 inches (114 cm), provided the guardrail. Sets forth safety requirements for areas where danger exists of persons or objects falling through floor or. If the employer chooses to use a guardrail system, he must comply with the following provisions: Top edge height of top rails, or equivalent guardrail system members, must be between 39 and 45 inches above the. Note that our enforcement guidance may be affected by changes to OSHA rules. The Occupational Safety and Health Administration (OSHA) standard at 29 CFR 1926. 1926. Particular industries require certain specifications on safety railing systems. 500, Guardrails, handrails & guards. OSHA has issued a final rule on Walking-Working Surfaces and Personal Fall Protection Systems to better protect workers in general industry from these hazards by updating and clarifying standards and adding. 502(b), including the top rail height requirement in §1926. As a reference, OSHA's fall protection standards would require a safety net used in this scenario to extend 8 feet from the edge of the walking/working surface. 1 m) plus or minus 3 inches (8 cm) above the walking/working level. Cal OSHA has a force requirement of 20 pounds per linear foot along the entire rail system. 29). Railing height from tread surface at the riser face shall be 33±3 inches (83. Guardrail systems should consist of a top and intermediate rail. 23 covers requirements for ladders and includes information on when handrails are required on mobile ladder stands or platforms (when they have a top step height of 4 feet or more) and how high a railing must be (29. gov) 202-366-6537. In some cases and places, however, that is not possible. 500, Guardrails, handrails & guards. 5”. 25 inches. 1431 (b) (2) Exceptions: A personnel platform is not required for hoisting employees: 1926. The top edge of the guardrail should be 42 inches above the walking/working surface. This letter constitutes OSHA's interpretation of the requirements discussed. If the guardrail is unable to bear the minimum structural load, it could break due to the applied forces, resulting in a tragic accident. An opening between 3½ and 9 inches should be avoided because of the danger of entrapment. OSHA Fall Protection Requirements. 1431 (b) (2) Exceptions: A personnel platform is not required for hoisting employees: 1926. Occupational Safety and Health Standards; Subpart: 1910 Subpart D; Subpart Title: Walking-Working Surfaces; Standard Number: 1910 Subpart D Title:. Compliance requirements for the use of U-bolt-type cable clamps in horizontal lifelines. The three major components of a strong post barrier are the rail, posts, and blockouts. An opening between 3½ and 9 inches should be avoided because of the danger of entrapment. Therefore, it is vital to assist the public in learning about OSHA documents related to agriculture. The following definitions apply in this subpart: Alternating tread-type stair means a type of. A guardrail is, first and foremost, a safety barrier intended to shield a motorist who has left the roadway. Depending on the type of scaffold, each employee more than 10 feet above a lower level must be protected from falling either by a personal fall arrest system, a. Common shapes are flat, rounded edge, and tubular in horizontal railings, whereas tetraform spear-headed or ball. This subpart applies to all general industry workplaces. Railing height shall be approximately 42 inches off the floor, platform, or other working surface, with a midrail between the toprail and the working surface. The Occupational Safety and Health Administration (OSHA) standard at 29 CFR 1926. l-l989, Safety Requirements for Floor and Wall Openings and (non-residential) Stair and Railing Systems. Use of personnel platform. [Note: for this section, the criteria and practices requirements for guardrail systems on scaffolds are contained in 29 CFR part 1926, Subpart L or 29 CFR 1915. When properly installed, our guardrail netting meets OSHA toe board requirements, ANSI/ASSE standards and NYC Local Law 61. OSHA published a final rule on walking-working surfaces and personal protective equipment in November 2016 that updated requirements for slip, trip and fall hazards. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. (note that all lumber dimensions are nominal lumber sizes. 501 ), any worker constructing a leading edge 6 feet or more above a lower level “must be protected by guardrail systems, safety net systems, or personal fall arrest systems. 1926. Cal OSHA has a force requirement of 20 pounds per linear foot along the entire rail system. The top edge height may exceed 45 inches (114 cm), as long as the guardrail system meets all other criteria. Department of Labor, OSHA, Office of Construction Standards and Guidance. Cal-OSHA’s 1. 1910. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA's and may have different or more stringent requirements. Slope between 30° and 50° from the horizontal. Regarding roof protection from falls for work on low-slope roofs, OSHA has general industry (1910) regulations based on various distances: Work done less than 6 feet from the roof edge:For other scaffolding guardrail requirements, see 29 CFR 1926. Keep away from the edge. This 28-page document covers the basics of fall protection systems, equipment, and regulations, as well as practical tips and examples for different work scenarios. ) from the surface of the walking area. 501(b)(13), workers engaged in residential construction six (6) feet or more above lower levels must be protected by conventional fall protection (in other words, guardrail systems, safety net systems, or personal fall arrest systems) or other. Handrail Height. These include: The top edge height of top rails, or equivalent guardrail system. Understand the requirements of OSHA’s Fall Protection standards at 29 CFR 1926, Subpart M, to protect workers exposed to falls six feet or more above a lower level. For more information, visit or call OSHA at 1-800-321-OSHA (6742), TTY 1-877-889-5627. 6300 W by NW Blvd #100, Houston, TX 77040 (800) 962-6111. The material and style of. Safety Railing and Guardrail Systems. Falls from heights and on the same level (a working surface) are among the leading causes of serious work-related injuries and deaths. The retaining wall safety device shall be designed and constructed structurally in accordance with. The job-built guardrail systems were evaluated to determine whether they complied with OSHA regulation 29 CFR 1926. This appendix serves as a non-mandatory guideline to assist employers in complying with these requirements. The employer must ensure: 1910. Maximum riser height of 9. The purpose of these guard rails is to prevent falls or unauthorized access to certain areas. They must be protected by guardrail systems, safety net systems, or personal fall arrest systems, or They must work in a controlled access zone (CAZ) . (2) If the required width of a ramp or flight of stairs is more than 2 200 mm, one or more intermediate handrails continuous between landings shall be provided, and located. 6 - Incorporation by reference. 26 (a) Dockboards are capable of supporting the maximum intended load in accordance with § 1910. Top edge height of top rails must be between 42 +/- 3 inches above the walking/working level, except when conditions. When figuring out the tolerances for the OSHA guardrail height, the minimum allowed is 39". This regulation states that, “Guardrail systems shall be capable of withstanding, without failure, a force of at least 200 pounds (890 N) applied within 2 inches (5. This regulation ensures that personnel and equipment are protected from a fall if/when the guard rail is struck by a piece of equipment or machinery. Guardrail systems and their use shall comply with the following provisions: – 1926. 555 (a) General requirements. According to OSHA guardrail requirements, a railing is required when working at 4 feet or more. This 200 pound load test is designed to stop an employee from a potentially fatal fall, as opposed to the IBC requirement that takes into account the idea that many people may be leaning on the railing at the same time. It covers all walking-working surfaces unless specifically excluded by an individual section of this subpart. • safety knowledge among workers varies, • manual labor is used extensively, • the climate creates year-round heat stress. An OSHA-approved state plan must have safety and health requirements at least as effective as those of Federal OSHA and must adopt comparable state they satisfy all of the guardrail requirements. 5". OSHA requirements are set by statute, standards and regulations. 26. The section of the OSHA code that specifies most of the primary guardrail and handrails as it directly relates to safety railing is 1910. [29 CFR 1926. GUARDRAIL 101. A handrail and a wall or other surface adjacent to the handrail shall be free of any sharp or abrasive elements. 23 covers requirements for ladders and includes information on when handrails are required on mobile ladder stands or platforms (when they have a top step height of 4 feet or more) and how high a railing must be (29. . Top rail at 42” to 45” and a midrail. 351. , an opening in the roof of a building through which persons may fall. The manufacturer must approve any alterations to the stilts. Scope . Safety Standards for Fall Protection in the Construction Industry. 62 cm). 502(k) and training that meets the requirements of 29 CFR 1926. Occupational Safety and Health Standards; Subpart: 1910 Subpart D; Subpart Title: Walking-Working Surfaces; Standard Number: 1910 Subpart D Title:. Mr. Most loading docks are 48-52” tall, but we do see instances of docks a few inches shy of four feet–say 46”. 26. The Safety Boot guardrail system is designed for this specific purpose, and when paired with the material listed above and properly fastened to the substrate, this bracket system makes it very easy to meets the OSHA requirements. I. 5. Contains information that helps workers identify and control the hazards that cause the most serious construction-related injuries. 29 (b) (1) The top edge height of top rails, or equivalent guardrail system members, are 42 inches (107 cm), plus or minus 3 inches (8 cm), above the walking-working surface. The section of the OSHA code that specifies most of the primary guardrail and handrails as it directly relates to safety railing is 1910. 2m) or more above a lower level is protected from falling by one or more of the following guardrail systems; safety net systems; or. Where the guardrail requirements of subsections (a) and (b) are impracticable due to machinery requirements or work. What are the general OSHA requirements of toe board? According to OSHA 1910. The Occupational Safety and Health Administrations, Safety and Health Regulations for Construction, specifically 1926. OSHA requirements are set by statute, standards and regulations. They must be protected by guardrail systems, safety net systems, or personal fall arrest systems, or They must work in a controlled access zone (CAZ) . Per 1926. OSHA eTool. A guardrail is a safety railing or barrier located along a horizontal surface such as a balcony, deck, or porch. Fall Protection. OSHA requirements are set by statute, standards and regulations. 23) do not directly address the spacing of posts in between sections of a freestanding modular guardrail system. 5 inches (24 cm); and. Answer. (1) For wood railings: Wood components shall be minimum 1500 lb-ft/in2 fiber (stress grade) construction grade lumber; (2) For pipe railings: posts, top rails, and intermediate. Minimum width of 22”. The agency has received numerous questions asking when handrails are required, and about the height requirements for handrails on stairs and stair rail systems. (4) If a doorway is located at a landing, then the. 2m) or more above a lower level is protected from falling by one or more of the following guardrail systems; safety net systems; or. (3) If ramps change direction at landings, the minimum landing size shall be 60 in by 60 in (1525 mm by 1525 mm). Paragraph (g)(4)(xiv) requires that guardrail systems using manila, plastic or synthetic rope as rails be inspected by a competent person as frequently as necessary to ensure that the guardrails comply with the performance criteria in final rule §1926. 451(g). This is the first OSHA requirement to be aware of. There are separate standards set by OSHA for General Industry and Construction. The short answer is usually, yes. . Purpose of a Guardrail . Department of Labor, Occupational Safety and Health Administration (OSHA) under the general industry standard 29 CFR 1910. * The CPSC recommends that. 4, and the lowest, a safety net that meets the requirements of section 26. Handrails must be placed between 34″ and 38″ in height, measuring from the nosing of the stair. Re: Guardrail requirements for two point suspension scaffolds Dear Mr. The IBC code for structural design has some very specific requirements for deck stairs: Stair rails on decks should be between 34 inches and 38 inches high, measured vertically from the nose of the tread to the top of the rail. Be sure you have checked all 10 before work begins on your job-site. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. 3-1984 entitled American National Standard for Ladders — Fixed — Safety Requirements, as amended from time to time, other than section 7 of that Standard. They must be installed according to manufacturer’s instructions. The safety ledge shall be designed to carry a live load of 100 pounds per square foot. need to be provided for(The requirements to have guardrail systems with toeboards for falling object and overhead protection on platforms and landings are set forth in subpart M of this part. 452(x)(9) 1926. 452(y)] 1910. 36″ to 38″ — may also serve as guard. 29(k)(1), the new toeboard requirement needs to be at least 3. 71(j) (1) and (2). 450(b) 1926. Thank you for your inquiry. 23 (e) (3) (v) (b)); Protection between top rail and floor,. Such workers when exposed to fall hazards of 4 feet or more must be protected by a standard railing. 502(c)(2). e. OSHA addresses the fall protection to be provided to employees on self-propelled scissor-lifts through the application of the general duty clause (section 5 (a) (1)) of the OSH Act) because the OSHA standards do not cover such equipment. 1. 5 - Applicability of standards. 29 (b) (3) (4) (5). Based on the relevant OSHA standards 1910. S. There is a 3-inch variance that is allowed in either direction. A stairway, ladder, ramp or other safe means of egress shall be located in trench excavations that are 4 feet (1. If the guardrail is unable to bear the minimum structural load, it could break due to the applied forces, resulting in a tragic accident. 29 (b) (3) (4) (5). 502 - OSHA's new fall protection standards for construction will prohibit use of safety belts with side dee rings as part of a personal fall arrest system - 09/25/1995 1926. 28 includes unprotected sides and edges. 22 m) or more in depth so as to require no more than 25 feet (7. Provides illustrated safety checklists for specific types of scaffolds. This threshold differs from 29. S. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. Guardrail requirements are covered under OSHA 1910. In these cases, a handrail must be mounted on at least one side if the stairway is less than 44 inches wide. Minimum 6′-8″ headroom height clearance for stairway.