(7) Where the rise would exceed 9 1/2 inches and the run would be less than 8 inches, portable, fixed, or ships ladders shall be used. OSHA 1910. OSHA requires that stairs be designed for 5 times the anticipated live load. 1) or greater from the deep end wall and the water depth at that location is. 7″ closed riser, max 4″ open gap. • Handrails and Stair rails: A. 6 %âãÏÓ 498 0 obj >stream hÞÔ–ÛŠÛ0 †_eÞ@ K. 2 Ceiling Height. A (half-tread width) B. 28 and 1910. 5 mm) tolerance could interfere with the rhythm of the stair user. Stairways. 23(e)(1) 1910. b. 36(c)(1) Each exit discharge must lead directly outside or to a street, walkway, refuge area, public. Vertical rise between treads is generally around 9". IBC also has the additional requirement of adding an intermediate landing on stairwells more than 12-feet high, as well as handrail extensions on the bottom. Section 1910. 2. Stairwells and Stairs. 28; (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. Featuring Lathams' Supagrit silicon carbide mineral fill. 22 from the list price if you will provide your own bracing for the system. 1053 (a) (1) (i) Each self-supporting portable ladder: At least four times the maximum intended load, except that each extra-heavy-duty type 1A metal or plastic ladder shall sustain at least 3. The step tread is the part of the stairs that you walk on. Thank you for your interest in occupational safety and health. 2. Summary:The International Residential Code (IRC) lays out the requirements for residential staircases. The section of a stairway leading from. Call Us Today: 856. OSHA's mission is to ensure that employees work in a safe and healthful environment by setting and enforcing standards, and by providing training, outreach, education and assistance. The IRC requires a minimum stair tread depth of 10 inches (254 mm) with a nosing projection of between ¾ and 1 ¼ inches (19-32 mm). Overall width of 23"; inside handrail width of 20". Handrails must not project into the stairway more than 4 ½ inches—so with one handrail, the stairway can’t be less than 31 ½ inches wide, as measured at or below the rail, and with two handrails, the. Exterior stair paces must comply because total to general stair tread requirements found in IBC section 1011. 25 Portable wood ladders. 3. OSHA Enforcement ; Annual Inspection Data ; Topics Back. More similar in landing requirements, both OSHA and IBC require landings at the top and bottom of the stairs. Construction Safety Orders Article 17. R311. Fire proof construction. Therefore, if your stair railings are 30-34" as specified in §1910. 3-stringer design with treads welded to the stringers. (. Designers can also provide a concrete slab edge angle detail that allows for adjustment by the detailer when the stair detailing is underway. Here are 5 benefits of complying with OSHA requirements: 1. 5, the minimum depth of the tread is 13 inches (330 mm) and not less than one handrail complying with Section 1014 is provided within 30 inches (762 mm) of the. There are also section codes in place for standard stair tread dimensions. 2 [Handrail] Top Extension at Stairs. The total concrete needed for the 3' by 3' porch will be . 6] Thank you for your March 3, 2000 letter to the Occupational Safety and Health Administration's (OSHA's) [Directorate of Enforcement Programs (DEP)]. OSHA requires railings on open sides of stairwells and a handrail on at least on the side, preferably the right side descending at 42″ high. Treads (the horizontal stair element you step on) that are at least 10 inches in depth and no more than 14 inches. [39 FR 23502, June 27, 1974, as amended at 43 FR 49744, Oct. The employer must ensure: (1) Handrails, stair rail systems, and guardrail systems are provided in accordance with § 1910. The winder treads shall have a minimum tread depth of 7 inches measured at a point 12 inches from the narrow end of the tread. Useful across all industries, this information will help you determine what is needed to ensure the safety of your employees and the product. Plastic composite exterior deck boards, stair treads, guards and handrails shall comply with the requirements of ASTM D7032 and the requirements of this section. 25 (Fixed Industrial Stairs) listed below price table. 05 cm), stair width a minimum of 22 inches (55. Stairwells and Stairs. REDD Team will help you meet OSHA standards for stairs and put fall-protection safeguards in place at your job sites. Section 1910. What if the doorway described in §1910. Before using a portable ladder, make sure that it meets general structure, structural integrity, and general safety standards (Figure 1). Stair structure, treads and risers shall be in sound condition, properly supported and anchored, and capable of supporting anticipated loads. Stair Width: A minimum 22″ wide stair. The riser height shall be measured vertically between the leading edges of adjacent treads. gov OR-OSH 03/20 S-04 HANDRAILS What are they? Handrails are rails that provide a handhold for support. Handrail Height. 29 (f) (1) (ii) (B)) and the handrail must be 30 to 38 inches in height (§1910. OSHA requirements are set by statute, standards, and regulations. Note: For specific code requirements, contact the Building Inspection Department at 952-442-7520 or 888-446-1801 or e-mail: info@mnspect. Means of egress doors shall meet the requirements of this section. 2. OSHA sets and enforces standards to assure safe and healthy working conditions for working men and women. The riser height shall be not more than 7 3 / 4 inches (196 mm). A nosing is not required where the tread depth is a minimum of 11 inches (279 mm). Smoothness of surface D. 17 cubic yards. Minimum tread width of 10 "- maximum difference among treads 3/8". Anchorage. A stair with a single riser or with two risers and a tread is permitted at locations not required to be accessible by Chapter 11 where the risers and treads comply with Section 1011. The Agency’s interpretations explain these require-. That’s why we’ve compiled this guide for OSHA stair requirements. R311. Stair Width: A minimum 22″ wide stair. (b) General requirements. OSHA 1910. 04(3)(b)6. 120 (b) (2) Stair landings shall be at least 20 inches (50. 1910. 23 that addresses stair railings is subsection (e) (2) and not (e) (1). That’s why we’ve compiled this guide to OSHA stair requirements. Enforcement. The railings must be capable of withstanding a force of at least 200 pounds applied in. 25 (Fixed Industrial Stairs) listed below price table. Maximum 12′-7″ vertical height (rise) for a flight of stairs. 25 (b) (4)] IBC requires the same width as OSHA. The IBC contains requirements for exit stairway enclosures that address fire-resistance and smoke protection, stairways and handrails, signs, and other features. and a vertical clearance above any stair tread to any overhead obstruction of at least 6 feet 8 inches. 8 Steel Framing for Concrete Stairs 2. 5 Stair treads and risers. be less than. 502(k). 21 (b) Definitions . B. Rise and tread measurements are dictated by the angle of the stairway rise. The maximum vertical distance between treads (riser height) is the same 18 in. ) (c) Rise and Run. 17, 2017, must be at least 42 inches. Elongated openings shall be placed so that the long dimension is perpendicular to the direction of travel. 7. 10, 1984] OSHA standard 1910. Under Stair Protection. 25(f)(1) Have a series of treads includes at a slope a 50 to 70 degrees from the horizontal; 1910. 5 cm*. (4) Headroom. These measurements are taken at the leading edge of the treads. At the top of a stair flight, handrails shall extend horizontally above the landing for 12 inches (305 mm) minimum beginning directly above the first riser nosing. 25” in any stairway; and stairways must be installed between 30 and 50 degrees from the horizontal. These regulations are crucial in safeguarding personnel and visitors, as well as avoiding costly penalties and lawsuits for non-compliance. It is important to note that in the most recent version of this ANSI standard, ANSI A1264. (See 81 FR 82611-12). To obtain an order form or copies of these codes, address: Department of Consumer & Business Services Oregon Occupational Safety & Health Division (Oregon OSHA) 350 Winter St. 5 Point A. Plastic ladders: ANSI A14. OSHA's requirements are set by statute, standards, and regulations. Part 1910. 6 cm) in any stairway netz. Labor Day: A Celebration Of Hard Work. The vertical sections of stairs, called stair risers, must be between 4 and 7 inches tall to be compliant with ADA guidelines. 1 specifies 100 psf min. Occupational Safety and Health Administration 200 Constitution Ave NW Washington, DC 20210 1-800-321-OSHA 1-800-321-6742. 2. For technical requirements for fire protection, see paragraph 2-2. 2. They’re available in 3", 9" and 11 ¾" step covers with stair nosing. IBC Stairs require guardrails of 42″ high and handrails of 34″ high on both sides of the stairwell. In general, the standards require the following: When there is a break in elevation of 19 inches (48 cm) or more and no ramp, runway, embankment or personnel hoist is. Each flight of stairs having at least 3 treads and at least 4 risers is equipped with stair rail systems and. The general requirements specified in Sections 1003 through 1015 shall apply to all three elements of the means of egress system, in addition to those specific requirements for the exit access, the exit and the exit discharge detailed elsewhere in this chapter. One of the more common issues with stair design is the lack of support pro-Intercommunicating stairway. 4-1979 - Safety Requirements for Job-Made Ladders. 25 – Stairways: 1910. OSHA Stair Requirements. OSHA 1910. Risers (the vertical element connecting treads) that are no less than 6 inches in height and no more than 7. 1052(a)(4). 505. The below table simply depicts these factors: OSHA IBC Risers & Tread 8″ open riser a 9. For the purposes of this section, dimensions and dimensioned surfaces shall be exclusive of carpets, rugs or runners. In addition, ANSI A10. Occupational Safety and Health Administration 200 Constitution Ave NW Washington, DC 20210 1-800-321-OSHA 1-800-321-6742. A nosing is not required where the tread depth is a minimum of 11 inches. 5″ riser has an angle of 45 degrees. 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. c. 8 kPa (100. Nosing – straight leading edge. See OSHA standard 1910. 7 m) or less of. Alliance ProgramAlliances enable organizations committed toworkplace safety and health to collaborate with. After reviewing your correspondence with enclosures, the following are suggested guidelines: A handrail and a stair railing have two different meanings. Solid or open tread surface is required;. STAIRMASTER anti-slip renovation treads are ideal for exit path markings, safety egress systems, steps and landings. It has comparable functionality to other grating types but has more tightly spaced cross bars. Among the requirements is the minimum stair width. Stairs with winders need to be at least 11″ deep and when 12″ in from the narrow edge and the minimum depth must be 10″. A spiral stair with these requirements that is shipped in one section will be an inexpensive, easy-to-ship. 5 metres apart measured verticallyThe PHP Guardrail System ensures OSHA compliance and protects anyone working within six feet of a roof’s edge or elevations over 48 inches. ( NOTE: If no nosing & solid risers, tread minimum is 11”. 8. The height of stair rail systems installed on or after January 17, 2017 is not less than 42 inches (107 cm) from the leading edge of the stair tread to the top surface of the top rail. and a vertical clearance above any stair tread to any overhead obstruction of at least 6 feet 8. 23 (e) (3) (iv), the anchoring of posts and framing of members for railings of all types. Subchapter 4. Stair Tread Anti-Slip or Coefficient of Friction Recommendations for Safe Walking SurfacesOSHA also drew many provisions in the final rule from national consensus standards, including ANSI/ASSE A1264. 28 (b) (11) (ii) Table D-2 contains a printing error, which OSHA will correct in a published notice. Note that our enforcement. (36″ wide areas served by less than 50 people) Railings & Guardrail: OSHA requires railings on open sides of stairwells and a handrail on at least on the side, preferably the right side descending at. Stair tread should be slip-resistant for mezzanine safety. OSHA req'mnts for stair loading. Remember to Include Flooring The terms “subdivision” and “subpart” are synonymous within OAR 437, Oregon Occupational Safety and Health Code. 7. Enforcement. Variations in riser height or stair tread depth shall not exceed 1/4 inch in any stairway system, including any foundation structure used as one or more treads of the stair;. OSHA general stair requirements Compliant fall protection (guardrail system) 2 3 Uniform riser heights and tread depths OSHA requirements for standard stairs 1 Slope between. In ad-dition to paragraph (b) of this section, the employer must ensure alternating tread-type stairs: (1) Have a series of treads installed at a slope of 50 to 70 degrees from the hor-izontal;IBC Requirements for Unoccupied Roof Egress. Some treads may include a nosing. 23 (e) (2), you are in compliance with §1910. Additional. R507. "One stair rail system with hand rail on each open side" is required. This includes, but is not limited to, requirements related to: general structural design, fire-resistant construction, light, ventilation, sanitation, plumbing fixture clearances, minimum room area and ceiling. 3 Exit Stair Handrails . 3 Floor Grating Treads and Platforms 2. Work Zone Traffic Safety. Balusters. Stair treads can come in non-slip varieties, particularly in commercial or industrial locations. Lack of B. A brief description of the OSHA Consultation Program, which is available to assist employers, is also included at the end of this publication. 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. Maximum 7-3/4 inch stair riser height. 25 (Fixed Industrial Stairs) listed below price table. A stair with a single riser or with two risers and a tread is permitted at locations not required to be accessible by Chapter 11, provided that the risers and treads comply with Section 1009. Standard Building Code Table 1203. Occupational Safety and Health Administra-tion (OSHA) style stairs are included, along with recommendations to determine ap-propriate core opening dimensions, and the guide can be used as an aid in determining code requirements related to typical stair and rail layouts. and a vertical clearance above any stair tread to any overhead obstruction of at least 6 feet 8 inches. com The employer must ensure: ( 1) Handrails, stair rail systems, and guardrail systems are provided in accordance with § 1910. The ‘nosing’ of the stair treads can be measured by placing a string line, or straight object, where each stair tread begins, forming a slope. Bound in content. Treads (the horizontal stair element you step on) that are at least 10 inches in depth and no more than 14 inches. 10, 1984] §1910. Handrail Distance From Wall 1-1/2" to 4-1/2". The regulations cited apply only to private employers and their employees, unless adopted by a State agency and applied to other groups such as public employees. 25(b)(5)(ii) and shown in figure D-7 is perpendicular to the direction of. 2. Recommendation: Providing visual contrast (light-on-dark or dark-on-light) on the top and bottom steps that is approximately 2 inches wide and located either on nosings or at the leading edges of treads is helpful for people with low vision. Risers (the vertical element connecting treads) that are no less than 6 inches in height and no more than 7. OSHA’s proposal focuses on two sets of situations: Correcting rail requirements for stairways narrower than 44 inches, and with 2 open sides, by inserting words accidentally omitted when the 2017 requirements were published: - from “one stair rail system [on] each open side”. The maximum and minimum cross-sectional dimension should be 2. § 50. 1839 Non-Sales: +1 (843) 264-3729. Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. Our line of stair nosings, treads, platforms and landings, in aluminum, bronze, nickel bronze and iron are designed for use in malls, transit industry, public buildings and schools, for interior and exterior applications. If you follow these requirements and adhere. 5)Occupational Safety and Health Administration, Department of Labor. , some states have adopted. 5 inches (24 cm). Spiral stairs must meet the vertical clearance requirements inLoad-capacity of 1,000 lbs. Fixed Industrial Stairs: OSHA Standard 1910. 1–2007, Safety Requirements for. 48±5. Training Requirements by Standard ; Enforcement Back. 25(b)(5)(ii) and shown in figure D-7 is. Tread width must be uniform. IRC Stair Nosing Requirements. Stair treads must sustain a weight of at least. 23(e), Railing Specifications. User note: About this chapter: Chapter 3 contains a wide array of building planning requirements that are critical to designing a safe and usable building. Interior stairs shall have the upper approach and lower tread marked by a stripe providing clear visual contrast. 24 3 Stair Treads All treads must be reasonably slip-resistant and the nosings must be of nonslip finish. The standard focuses on proactive safety management — meaning that OSHA expects employers to find and fix workplace hazards BEFORE they become an issue. 25 inches. OSHA requires railings on open sides of stairwells and a handrail on at least on the side, preferably the right side descending at 42″ high. a 9. 4. 9 that "[f]lights of stairs, uninterrupted by landings,. Plastic composite deck boards and stair treads, or their packaging, shall bear a label that indicates compliance to ASTM D7032 and includes the allowable load and. it is important to ensure that the OSHA criterion is also referenced in the performance requirements for stair design in the project specifications. 5”. Occupational Safety and Health Administration 200 Constitution Ave NW Washington, DC 20210 1-800-321-OSHA 1-800-321-6742. 51 m) in width, of adequate strength, maintained in safe repair and safely secured shall be used. For Employers ; Worker Rights ; Workers Memorial ;. Handrails shall be at a uniformly height above walking surfaces, stair nosings, additionally ramp flat. Winter Driving. 05 cm), stair width a minimum of 22 inches (55. The uniformity of risers and treads is a safety factor in any flight of stairs. 7″ closed riser, max 4″ open gap. ) (c) Rise and Run. 25 (b) Compliant fall protection (guardrail system) Uniform riser heights and tread depths . This web page provides the OSHA standard number, title, and subpart for the requirements of stairways and ladders in construction. Handrail And Guard Code. The OSHA stair headroom clearance requirements are found in OSHA 1910. Training Requirements by Standard ; Enforcement Back. to a. OSHA requirements are set by statute, standards, and regulations. Maximum 12′-7″ vertical height (rise) for a flight of stairs. a. Source: 39 FR 23502, June 27,. 5 “width below handrail height where a handrail is on one side. Handrails may project from each side of a stairway a distance of 3 1/2 inches into the required width. OSHA requirements are set by statute, standards and regulations. In the U. A ladder or stairway must be provided when the worksite has a break in elevation of 19” (48cm) or more, and there is no runway, ramp, embankment, or personal hoist for workers’ access. A ship's ladder must have toe clearance of 7 inches unless the nature of the work requires a lesser clearance; 4. 88 cm) between vertical barriers, tread depth a minimum of 12±2 inches. Finger clearance: Minimum clearance between aTraining Requirements by Standard ; Enforcement Back. 5 Stair treads or risers. ASAE S211. 05–20 of this chapter. The elements of a safety and health program that can be used by employers to develop effective programs at their work sites. 21 (b) Definitions . If the handrail isn’t circular, the perimeter dimension should not be less than 4 inches and mustn’t be greater than 6. Ceilings of dwelling units and sleeping units within residential occupancies in accordance with Section 1207. 1 Section 504. 5 and 18 cm*. Like the IBC, OSHA dictates specific measurements. For example, stairs manufactured with a 45-degree stairway rise must have a minimum rise and tread of 8. Minimum tread depth of 9. Tread depth at walk line shall measure a consistent 12 inch distance from the side of the stairway, shall be uniform. Outdoor stair treads must comply with all the general stair tread requirements found in IRC section R311. Stair safety in the home is an important issue often overlooked. For the purposes of this section all dimensions and dimensioned surfaces shall be exclusive of carpets, rugs or runners. Variations in riser height or stair tread depth must not exceed 1/4 inch in any stairway system,That part of §1910. 36 inches. The following requirements apply to all stairways as indicated: (a) Stairways that will not be a permanent part of the structure on which construction work is being performed must have landings of not less than 30 inches (76 cm) in the direction of travel and extend at least 22 inches (56 cm) in width at every 12 feet (3. 1-800-321-OSHA 1-800-321-6742 We hope you find this information helpful. Vertical rise – 30° to 50°. OSHA says exposure to these types of hazards pose a. • Recognizes and clarifies design requirements for buildings within tsunami inundation zones. 24 to 19. NITEGLOW photoluminescent epoxy filler extends uniformly throughout. 1052(a)(1) which requires a minimum width of at least 22 inches. 24 (i) "Vertical clearance. 2 allows access to unoccupied roofs to be a roof hatch or trap door. OSHA set the design requirements for alternating tread stairs included teil 1910. Treads shall be 11 inches (280 mm) deep minimum. Handrails not shown for clarity. Handrail Required On One Side If 4 Or More Risers. Spiral stairways for normal employee use must have a stair width of at least eleven inches as measured from the center of the stair to the edge. 26. ) Reply #2: Yes. 78 cm), respectively. Ladder safety devices and related support systems for fixed ladders shall meet the following requirements: All safety devices shall be able to withstand, without. Stair treads and risers shall meet the requirements of this section. 24 (a) (3) Step bolts are uniformly spaced at a vertical distance of not less than 12 inches (30 cm) and not more than 18 inches (46 cm) apart, measured center to center (see Figure D-6 of this. (a) Application of requirements. The IBC mandates a minimum tread depth of 11 inches (279 mm) for commercial staircases, with nosing projections between ¾ and 1 ½ inches (19-38 mm). and a vertical clearance above any stair tread to any overhead obstruction of at least 6 feet 8 inches. Where supported by attachment to an exterior wall , decks shall be positively anchored to the primary structure and designed for both vertical and lateral loads as applicable. This is measured from the top surface of the handrail. Entered does not osha stair tread requirements request such authorization from the accuracy or contents, takes no control over the destination server. The stair will be installed at a 70-degree angle or less. In the 2016 rulemaking, OSHA had allowed the top rail of stair rail systems to serve as a handrail when two conditions were met: (1) The height of that stair rail system is not less than 36 inches and not more than 38 inches, as measured at the leading edge of the stair tread to the top surface of the top rail; and (2) the stair rail system was. 2120. Guard Required If Dropoff Is 30-Inches Or More. For complete information, see the moved sections table in. For Employers ; Worker Rights ; Workers Memorial ;. Training Requirements by Standard ; Enforcement Back. 08 cm), and tread nosing shall be straight leading edges. Submit manufacturers' product data for following items for approval: 1. 5 inches at the walk line, a riser height maximum of 9. For projects falling under the IRC, the minimum tread depth is 10 inches, plus a required nosing of at least ¾ inch. 2003 ANSI A117. (iv) Have treads and landings of slip resistant surfaces. B. 88 cm) between vertical barriers, tread depth a minimum of 12±2 inches (30. OSHA’s proposal focuses on two sets of situations: Correcting rail requirements for stairways narrower than 44 inches, and with 2 open sides, by inserting words accidentally omitted when the 2017 requirements were published: - from “one stair rail system [on] each open side”. Complete Bar. Minimum 31. S. A. CA: For spiral stairs, all treads should have minimum run not less than 150 mm, and an average run not less than 200 mm. 2. • Vertical clearance above any stair tread to an overhead obstruction shall be at least 7 feet measured from the leading edge of the tread. This letter constitutes OSHA's interpretation of the requirements discussed. Meets OSHA requirements. 29(b)(2)(iii) Keeping up with legislation. 04. The porch also has 9 linear feet of 6" step. The tread depth code for residential stairs. A stair rail may serve as a handrail only when the top surface of the top rail is between 36 and 38 inches from the. ; A stair with a single riser or with two risers and a tread is permitted at locations not required to be accessible by Chapter 11,. Are all treads reasonably slip-resistant with the front protruding edge of the tread. (d) The narrowest width in a stairway or landing serving a stairway shall determine the units of width for the. S. 5. 29(d) Designated areas. Minimum width of 22”. Handrails (continuous) are required on at least one side of flights of stairs with ≥ 4 risers. The Agency’s interpretations explain these require-. The Agency’s interpretations explain these requirements and how they apply to particular circumstances, but they do not create additional employer obligations. This section covers the general requirements for stairways, including standard, spiral, ship, and alternating tread-type stairs, such as the height, depth, width, and clearance of each tread. 2. A minimum tread width of 10 “- maximum difference among treads 3/8”. It is true that adequate attention. 2. Stairways include standard, spiral, alternating tread-type, and ship stairs. (2) Trim shall not reduce the required width by more than 3 1/2 inches. 5 and 35. 1 -2007, Safety Requirements for Workplace Walking/Working Surfaces and Their Access; Workplace, Floor, Wall and Roof Openings; Stairs and Guardrails Systems, the standard now states in Section 6. 4, the minimum depth of the tread is 13 inches (330 mm) and at least one handrail complying with Section 1012 is provided within 30 inches (762 mm) of the. The means of egress shall have a ceiling height of not less than 7 feet 6 inches (2286 mm) above the finished floor. 452(g)) subpart L regulate a similar type of scaffold, the carpenters' bracket scaffold. 5 Stair treads and risers. In any stairway, the tread depth and nosing depth have a maximum permitted variation of ⅜ inch. For stairs, a barrier of at least 865 millimetres high above the ‘nosing’ of the stair treads is required. At a point less than 12’ in elevation, this spiral stair has a rest landing which is also an OSHA requirement. Ramps should have an inclination of not. Additional requirements for ladders used on or with scaffolds are contained in subpart L—Scaffolds. 5 inches. osha. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. Figure D-12 -- Handrail Measurement. The maximum permitted nosing is 1. 1- 2000 Safety Code for Elevators and. Therefore let us recap on the residential stair code requirements: Minimum 36 inch clear width for stairway. c. 7. What if the doorway described in §1910. This section is intended to prescribe rulesMaximum 12 feet vertical height (rise) for a flight of stairs. 1604.