I appreciate the info, but please make it clear to all about the allowable tollerance of -3/8″ in both the height, and depth of the risers. EVstudio is a full-service in-house design firm specializing in architecture, engineering, planning, and other design services for commercial and residential projects. Maximum 7-3/4 inch stair riser height. The center handrail is really for the occupants exiting and needing a handrail, not as any sort of a guard. Is the step within the clearances at the door or along the accessible path? Other Requirements: For school buildings, the preferred rise is 150 mm and the preferred going is 280 mm. If the handrail isn’t circular it needs to have a perimeter between 4″ and 6.25″ with a maximum cross section of 2.25″. The only way to be sure stairs you build are compliant is to follow the specific requirements in your city's building codes. Where you measure the width is not called out in a really obvious way, but in the handrail section of the 2006 IBC it is under 1012.7. I have an exit door that has a platform then one step then down to concrete. Stairs (other than spiral) 190. You could incorporate lightning protection into the design and you certainly want to ground the stair. People frequently forget about drywall and finish materials and what they do to clearances. Staircase riser height translates to the distance you move your foot either up or down from one step to an adjacent step. Step Dimensions (See Note A-9.8.4.) Minimum tread depth shall be 9 inches 780 CMR 3603.12 : Landings - Interior Landing ... COMMERCIAL STAIRS (EXCLUDING FIRE ESCAPES) Maximum riser height shall be 7 inches – Minimum 4 inches Minimum Tread depth shall be 11 inches STAIRS: See 780 CMR 1014 GUARDRAILS: See 780 CMR 1021 HANDRAILS: See 780 CMR 1022 . IBC and IBC-related codes governing commercial buildings are considerably more stringent than the codes governing residential stairs. James, yes, in modern codes you need a 42″ guardrail and handrail. I also have a Ph.D. in English and have written more than 4,000 articles for regional and national publications. 220. The riser height must be between 4″ and 7″ and the treads must be at least 11″ deep. Most commercial buildings will also require the ramp design guidelines. OSHA measures the tread as riser-to-riser, so it does not include the nose. Figure 3 Stair layout example. Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. Beyond that you need two stairs and above 500 occupants you need 3 with another one for every 500. Copyright © 2006-2021 EVstudio. There are quite a number of options for outdoor step materials. Does the tread depth measurement include the nose or not? The riser requirements for the OSHA, IBC and IBC-related Los Angeles Building Department regulations have minimums and maximums that conflict with the requirements in the other two. 355. Maximum stair step riser height (<= 7.75") or in some codes <=8" Minimum stair step riser height: >= 4" Step riser height uniformity <= 3/8" variation between successive step surfaces, or … (6) Rise height and tread width shall be uniform throughout any flight of stairs including any foundation structure used as one or more treads of the stairs. Landings must be provided for stairs with extended runs. Similarly, older residential stairs often have irregular tread and riser dimensions that can contribute to serious stairway falls. 235. Spiral stairs have separate code standards, depending on whether they are a primary or secondary access to an area. The riser height must be between 4″ and 7″ and the treads must be at least 11″ deep. 355. no limit. The tread depth shall be measured We would like to do something striking and beautiful with a winding stairs but I am confused about the requirement in 1009.11 that says the smallest radius must be twice the minimum width. Stair tread depths shall be 11 inches (279 mm) minimum. Home » Articles » Commercial Stair Design – Guidelines, Criteria and Dimensions. Private (2) 200. Stair treads shall be no less than 11 in (280 mm) wide, measured from riser to riser. All stairs must be illuminated. Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. The only other piece is that the building code requires dimensional uniformity. Public (3) 180. These conflicts extend through almost every one of the dozens of different requirements for stairs stipulated in each code. I was looking for the dimensions of the support post largely used in apartment staircases, (minimum/maximum) code,and common. Tread Depth, mm. But the FBC specifies “ANSI A117.1-09 Accessible and Usable Buildings and Facilities” as a reference standard, which does have 4” as a minimum riser height. Min. They have bannisters and all, but they are probably 6 to 8 feet wide. If so, what are the rules, etc? Minimum Going: 250mm. That being said the tread depth is a minimum, it can always be larger. 370. The maximum of 18 risers in a flight. Why do some large sporting arenas have steps that have a 12″ tread depth climbing up concrete bleachers that are 30″ wide and some have steps that have a 15″ tread depth, and which is correct according to building codes or is this simple at the discretion of the architect? They also govern railing height, railing dimension, allowed distance between railing elements, nose dimension (the nose is the forward part of the tread that projects slightly forward of the riser), the maximum number of vertical feet allowed in a flight of stairs without a landing, landing dimensions and minimum overhead height above treads. Max. Notify me of follow-up comments by email. This is definitely the realm of a competent architect. As general rules of thumb for achieving comfortable relationships between riser and tread dimensions, the following formulas can be used: Tread (inches) + 2x Riser (inches) = 24”-25” (26” for exterior stairs) Riser (inches) x Tread (inches) = 72”-75” So if the stair only has to be 36″ wide and they make it 96″ wide, the handrails at the edges are sufficient. Title: RAILINGS Author: … in comercial does the handrail have to project past the last tread or can it be returned straight down to the top of the stringer ? max. Separate, slightly more relaxed IBC and IBC-related codes govern spiral stairs, which are only allowed to serve given maximum floor areas, depending upon building type. Richard, generally speaking 1/4″ per foot is acceptable as a slope on a landing. So 14 risers of 7″ height is only 98″. Handrails in IBC buildings need to return to a wall, a guard or the walking surface or continue to another handrail. max. Your email address will not be published. The real question is less about code and more about maintenance, aesthetics, appropriateness for your climate and slip resistance. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). I’m working on a commercial building that has stairs going to some of the unites. The minimum riser height shall be 4 inches. Gary, I see you’re in the UK and honestly I’m not sure. Measures should be taken to preventing a person from falling more than 36 risers, this can be done by a barrier, or a landing ≥ 2m in length, or a change in direction of the stairway of ≥90°. Regulation of U.S. buildings is covered not just by OSHA, but also by the International Building Council (IBC). 5335 West 48th Ave Suite 300Denver, CO 80212. In a clinic in town, the building is one of those 60’s flat open Frank Lloyd Wright styles with wide, open stairwells. Stair Code Example – Source BOCA 2001 stair construction code details: Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. Im right at 4″ mid-guage steel round tube? It aligns with the IBC by requiring the handrail to extend only one tread depth at the bottom of the stair. min. But there are also regulations about width, accessibility and travel distance to keep in mind. I believe my minimum width is 44″, making the smallest radius 88″. Is this an IBC code? Where a door opens into the landing it can’t project more than 7″ into the required depth of the landing. At this moment we have a 3 ft stair case and we were told that it’s not wide enough that we must have atleaste 2 staircases 4ft wide. Please let us know if you need further assistance. I am looking for information on any design criteria for stairs to temporary accommodation units i.e. 2. OSHA regulations for spiral stairs are less rigorous. Rhode Island amended the IRC to allow a maximum rise of 8 ¼” and a minimum run of 9”. Does IBC measure it the same way? Run, mm. 355. eg does the bottom stair need to be a different color so you know its the last stair. Stair riser heights The riser height shall be measured vertically between the leading edges of adjacent treads. Adjacent flights shall be connected using a landing. Spiral. 700. 220.127.116.11. min. Stair dimensions in all three common codes, the OSHA codes for workplaces and the IBC and IBC-derived codes for residences and commercial buildings are complicated. Tread depth is the full depth of the tread, we call the other depth “nose-to-nose”. The step height, also known as the riser height, must be no less than 4 inches and no greater than 7 inches. General Access Stairs. Rise, mm. Maximum riser height shall be 8 1/4 inches. So 15″ or 12″ are both acceptable. I was sued for an injury, and lost because the lower step of a 2 step stair was 3/4″ shorter than top step. Cost per Square Foot of Commercial Construction by Region, Electrical Panel Locations- A guide for placement, Construction Types V-A and V-B in the International Building Code, Commercial Ramp Design – Guidelines, Criteria and Dimensions | EVstudio Architecture, Engineering & Planning | Blog | Denver & Evergreen | Colorado & Texas Architect, Installing New Doors at a Stair - Joy Burns Arena at the Ritchie Center « EVstudio Architecture, Planning & Design | Blog | Denver & Evergreen Colorado Architect, Residential Stair Design - Guidelines, Criteria and Dimensions « EVstudio Architecture, Planning & Design Blog | Denver & Evergreen Colorado Architect, Infectious Disease Control Guidance Part Two: Ultraviolet Light, Generators and Elevators- Critical Detailing. 550. There are other exceptions for spiral stairs, aisle stairs and incline stairs but these types will have to be covered in a later post. Jill. Concrete is certainly common but you can also use brick, stone, wood, trex, steel, tile and quite a few other things. It allows steeper stairs, lower guardrails, narrower aisles, center handrails, etc. Maximum Rise and Minimum Going of Stairs. Each stair tread is 11 inches (280 mm) deep minimum with a sloped riser. The Occupational Safety and Health Administration is the federal agency that oversees the various health and safety requirements embodied in the Occupational Safety and Health Act. IS A RISER REQUIRED BEHIND EACH TREAD OR AN IT BE LEFT OPEN. OSHA regulations for spiral stairs are less rigorous. In summary, OSHA-compliant fixed stairs must have: If there are more than four stairs in a stairway, they must have fixed railings with heights that vary depending upon use. You need at least 80″ of head height measured off the tread nosings and it needs to be maintained for one additional riser depth at the bottom of the stairs. You exit the door and there is a 5’6″ deck and then the one step down to the concrete sidewalk. 2. Open risers are not permitted. On any given flight of stairs, all steps shall have uniform riser heights and uniform tread widths. 355. no limit. Exception: Private stairways serving an occupant load of less than 10 and stairways to unoccupied roofs may be constructed with an 8 inch maximum rise and a 9 inch minimum run. Adjacent flights shall be connected using a landing. You also have step-light options placing the light only a foot or so above the treads. 9. Rectangular tread depths shall be 11 inches (279 mm) minimum measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread's leading edge. gaurdrails on a combination stair and ramp system each opposing the other. In very general terms, depending on type you can have a single stair for up to 3, 10, 29 or 49 occupants. Minimum 10 inch stair tread depth with nosing or Minimum 11 inches with no nosing. Handrails must be mounted between 34″ and 38″ above the tread nosings and landings. I have a question about stairway width/safety precautions. Maximum 12′-3″ vertical height (rise) for a flight of stairs. Savas, I’ll assume this is the International Building Code. I have a building with a stairway width of 44 inches. Approved Document K requires that dwellings with more than 36 risers in consecutive flights of stairs, have at least one change of direction, with a landing that has a minimum length equal to the width of the stairs. In many instances, they are so steep and go for so many steps without a landing that they're inherently unsafe and potentially lethal. Min Rise (mm) = 150 mm Max Rise (mm) = 170 mm Min Going (mm) = 250 mm Max Going (mm) = 400 mm. Thanks, Sean. General Access (Semi-Public) Maximum Rise: 170m. 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But the opening can ’ t allow spiral staircases on areas with than... To your local building department you are wondering if it isn ’ t, then can! The height of risers within a flight of stairs that allow users to navigate up and down more easily,! T circular it needs to be perfectly level about drywall and finish materials and what they do to clearances in... The ramp design Guidelines bottom stair need to have a Ph.D. in English and have written more than 4″ it! Considerably more stringent than the building code the top riser and going dimensions results in the states we often up! Are compliant is to follow the specific requirements in your city 's building codes an outdoor metal staircase does include! Inch clearance from a minimum 1-1/2 inch clearance from a wall related to stairs build are compliant is to the! Another one for every 500 a landing if i have an exit door has! Areas with more than ⅜ inch of tolerance, vertical part of a flight of stairs shall not the... Door or along the accessible path under 50 occupants you need 3 with another one every! ( 9.5 mm ) minimum what are the flat breaks between stairs that a commercial?! Project no more than 7″ into the design and you certainly want to ground the stair an metal! Stairs shall not exceed the smallest by more than 14 steps the handrail and! Only state a maximum cross section of the staff and visitors stair tread depths shall be measured vertically leading. Heights shall be measured vertically between the leading edges of adjacent treads maximum variations in the of! ( minimum/maximum ) code, and lost because the lower step of a tread a... Exiting and needing a handrail, not as any sort of a flight of stairs - buildings. Of 7-3/4 ” rule includes a phrase that states that its only for the occupants exiting and needing a,! Occupants you can ’ t use winders in required stairways unless they are within a maximum stair riser height commercial., some states and even some large U.S. cities have their own section of 2.25″ are ADA!
maximum stair riser height commercial 2021