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What is the correct slope for a ramp?

The desirable ramp slope standard, one inch of rise in 12 inches of run (about 8.3 percent slope), has been adopted by most building codes regardless of whether or not the access ramp is specifically for people with disabilities.

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Building Access Ramp Slope or Pitch Requirements

Recommended Access Ramp Angle Slope & Run Length POST a QUESTION or COMMENT about building access ramp construction codes, specifications, hazards, & safety improvements InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website. Building access ramp slope, pitch or angle specifications & codes: this document provides building code specifications, sketches, photographs, and examples of defects used in inspecting indoor or outdoor building access ramps. We also provide an ARTICLE INDEX for this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Building Access Ramp Slope or Pitch Requirements

Bottom line: recommended ramp slope:

The preferred slope for a building access ramp is 1:12 or 1 inch of rise per 12 inches of horizontal run - that's roughly an 8% slope also written as a 4.8 degree angle slope. While you will see ramps at steeper slopes including the range of 0° to 18° of slope in the illustration shown here and ramps with slopes as steep as 20° in older texts, to build a ramp that is compliant with the U.S. ADA, the maximum (steepest) ramp slope allowed is either: Maximum Egress Ramp Slope = 1:12 slope = 8.33% slope = a 4.76° degree slope Other Ramps Maximum Slope = 1:8 slope = 1.5:12 slope = 12.5% slope = 7.13° slope

Definition of a ramp

In the U.S. per the US ADA (Americans with Disabilities Act), a ramp is a sloping route constructed with a slope greater than 1:20 (one inch of vertical rise for every 20 inches of horizontal length, or run) and must conform to the standard ADA specifications for ramps. Ramps must [also] be a minimum of 36 inches wide [and require guardrails and graspable handrails - Ed.] This article series on access ramp design & construction explains and illustrates the requirements for safe, usable interior and exterior access ramps in buildings.

[Click to enlarge any image]

For example a steeper slope may be permitted on non-access ramps.

For complete details about building access ramp construction: slope, width, railings, non-slip surfaces, steps, landings at ramps, etc. See the standards, code, and ADA REFERENCES at the end of this document. The combination of a sloped surface with conditions that can make that walking surface slippery, especially at outdoor building access ramps, forms a falling hazard at both ramp ascent, and ramp descent for nearly everyone. These hazards are particularly increased if the ramp pitch is too steep. The desirable ramp slope standard, one inch of rise in 12 inches of run (about 8.3 percent slope), has been adopted by most building codes regardless of whether or not the access ramp is specifically for people with disabilities. Our illustrations above and below describe the recommended slope range for building access ramps, fixed stairs, and other structures. It will come as no surprise that the effective slope of a fixed stairway is considerably steeper than that allowed for access ramps.

Technical Details of Maximum Ramp Slope

If a building access ramp (also called an egress ramp) is located within an accessible route of travel and is used as a means of egress (exiting from a building), the ramp slope should be 1:12 (4.8 degrees, 8.3 percent) or less in the direction of travel. This standard is reflected in at least four building standards: UBC 1003.3.4.3, BOCA 1016.3, ADA 4.8.2, IBC 1010.2, and is elaborated in an excellent book that we recommend on stairs and ramps, Slips, Trips, Missteps and Their Consequences, by Bakken et als, found in REFERENCES at the end of this article. If the ramp is NOT located within an accessible route of egress (say a ramp giving access between the street and an elevated sidewalk), the slope of the ramp may be a little steeper (1:8 rather than 1:12, or 7.1 degrees, or 12.5 percent) in the direction of travel. Incidentally, depending on terrain, a ramp may slope upwards towards a building entry/exit door, or it may slope downwards towards the entry door. In either case, the ramp slope rules and standards are the same and the trip/fall hazards are essentially the same.

How to measure the slope of an access ramp

Project a horizontal line

(use a string, level, and stake if it helps) outwards from the uppermost end of the ramp - say the building entry platform - and the end of the ramp. Keep this line dead level. Measure the Ramp's Rise: Measure the height (the vertical distance) from the horizontal line to the ground surface at the end of the ramp or its landing platform. This is the total rise of the ramp. Measure the Ramp's Run: Measure the ramp's total horizontal distance from one end of the ramp to the other - say from the point at which the ramp reaches a level building entry platform or entry door to the opposite end of the ramp. State the Resulting Ramp Slope: Simply write the total rise divided by the total run to express the slope as a percent (1 inch of rise / 12 inches of run = 8.3% slope), or write the slope as a ratio such as 1:12, also expressed as "one in twelve".

Ramp Slope Example 1: a ramp with a slope of 1:12

Ramp Slope Example 2: a ramp with a slope of 4:12

If the ramp is twelve feet long (144 inches) and the total rise is four feet (48 inches) then the slope of the ramp is 48:144, or simplifying by dividing both sides of the equation by 12, the slope of this ramp is written as 4:12 (and the ramp is too steep, likely to result in a fall). Throughout this article series and in other documents you may see slope expressed as unit rise over unit run, such as 4:12 (4 inches of vertical rise in 12 inches of horizontal run), or you may see the same slope expressed as a percent (unit rise divided by unit run), or slope expressed in angular degrees.

A 4:12 slope ramp = a 33% slope = 18.26 degree slope.

Access Ramp Maximum Run Length

2019/03/01 jack said:

How long can a ramp run before you need a flat landing area ?

Illustrations [above and below] on which we indicate a 30 ft. or 40 ft. (depending on slope) maximum-recommended access ramp length for a single run before reaching a landing or platform, adapted from the United States Access Board,

retrieved 2019/03/01 original source: https://www.access-board.gov/guidelines-and-standards/buildings-and-sites/about-the-ada-standards/guide-to-the-ada-standards/chapter-4-ramps-and-curb-ramps and from https://www.ada.gov/reg3a/fig16.htm

[Click to enlarge any image]

and

Figure 16. Components of a Single Ramp Run and Sample Ramp Dimensions.

Components include a level landing at the top of the ramp, the surface of the ramp and a level landing at the bottom of the ramp.

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The rise of the ramp is the vertical dimension and the horizontal projection or run of the ramp is the horizontal dimension. If the slope of a ramp is between 1:12 and 1:16, the maximum rise shall be 30 inches (760 mm) and the maximum horizontal run shall be 30 feet (9 m). If the slope of the ramp is between 1:16 and 1:20, the maximum rise shall be 30 inches (760 mm) and the maximum horizontal run shall be 40 feet (12 m). A4.8.2 Slope and Rise. Ramp slopes between 1:16 and 1:20 are preferred. The ability to manage an incline is related to both its slope and its length. Wheelchair users with disabilities affecting their arms or with low stamina have serious difficulty using inclines. Most ambulatory people and most people who use wheelchairs can manage a slope of 1:16. Many people cannot manage a slope of 1:12 for 30 ft (9 m). 4.8.4* Landings. Ramps shall have level landings at bottom and top of each ramp and each ramp run. Landings shall have the following features: (1) The landing shall be at least as wide as the ramp run leading to it. (2) The landing length shall be a minimum of 60 in (1525 mm) clear. (3) If ramps change direction at landings, the minimum landing size shall be 60 in by 60 in (1525 mm by 1525 mm). (4) If a doorway is located at a landing, then the area in front of the doorway shall comply with 4.13.6.

Access Ramp Landing slope

Separately from the slope of the access ramp walkway itself, in some situations a landing or platform may be required along a rampway, depending on the ramp length and the requirement for turning space.

Also see RAMP LANDING CODES.

Landings shall have a slope not steeper than one unit vertical in 50 units horizontal (2-percent slope) in any direction. Changes in level are not permitted. - Florida Building Code 1010.6.1 Landings.

thank you.

Blue

In the case you describe the local building inspector is your final authority. Any other opinion is merely that. The escalator landing is 5" higher than the floor. To reduce the tripping hazard it was recommended to have a ramp. Given the space available a slope of 1:8 is not possible. Will a 2-feet ramp 5:24 slope acceptable by code? Not an ADA and not an emergency egress but serves the hotel guest in gatherings. Current code use is IBC2009

I am putting a 2-feet ramp on an escalator landing that is 5-inches higher than floor. The short ramp slope is 5:24 (20.83%). Without the ramp it is acceptable by code. If I place a 2-feet short ramp will I violate the IBC code?

Roma

The ADA and equivalent laws in other countries than the U.S. expect you to make a public exhibition hall readily accessible to people in wheelchairs, not just to people who can climb stairs. That means providing properly-designed access ramps. The article on this page describes access ramp slope requirements. You are welcome to review all of these articles found also in the ARTICLE INDEX

RAMPS, ACCESS - home

RAMP BUILDING CODES

RAMP LANDING CODES

RAMP RAILING CODES

RAMP SLOPE or PITCH

RAMP SLIP TRIP FALL HAZARDS

RAMP SLIP TRIP FALL REDUCTION

and I'll welcome any follow-up questions that arise

Have I missed something?

My project is EXHIBITION FACILITY CENTER where I have provided 2 halls of 3,000 Sq. M. each and also the same on first floor. As the height of the hall is 8 M. should I provide stairs or ramps? and how? What would be the calculations criteria of both. Please let me knwe ASAP. Thank You. Thank you for the reminder on the browser! I think that's exactly what my last disconnect was prior to the previous comment I had posted. Sorry for having repeated myself after you had already sorted things out. Thank you again for your patience and assistance! Be sure to clear your browser cache before refreshing the page so that you were seeing the latest version

Thank you Luke. I thought this was corrected

I will review again to see if there are still other occurrences where degrees are mixed up with rise or run numbers Sir, thank you for all the references and examples. I assure you that I did make the effort to use the great references section you provided and looked through the IRC and the IBC prior to asking. I've found very similar to what you provided from the 2018 IRC reflected in the 2018 IBC, sections 1012.2 and 1029.14.1. I think you and I are in agreement in our reading of the various applicable codes but not in our interpretation of the text above on this page. I believe the crux of the disparity is the units of measurement. My confusion isn't around the numerical value of 20, it's that the text above says twenty DEGREES and the picture above also indicates a maximum of twenty DEGREES, while of the references I've been able to find and of what you've provided in your previous replies, when slope or percentage is converted to degrees, the maximum allowable slope is 7.13 DEGREES; far under the twenty indicated above. I don't disagree that references are made to a 1 (vertical) : 20 (horizontal) slope ratio, however, as you've well indicated with the provided conversions, both slope RATIO and slope PERCENTAGE are simply not the same as DEGREES. I'm certainly open to the idea that my understanding of this is flawed so I very much thank you for your time and your patience with these questions.

Luke

You are dead right, I had typos in the original article - I'm correcting my own mis-speaking between slope expressed as rise:run vs degrees vs %

Thank you so much for taking time to question my error.

the U.S. per the US ADA (Americans with Disabilities Act), a ramp is a sloping route constructed with a slope greater than 1:20 (one inch of vertical rise for every 20 inches of horizontal length, or run) and must conform to the standard ADA specifications for ramps. Ramps may have a maximum slope of 1:12. A 1 in 12 slope = an 8.33% slope = a 4.76 degree slope. The "bottom line" section above says "the preferred slope for a building access ramp is between 7 and 15 degrees, and permitted slopes range between 0 and 20 degrees." However, I'm having difficulty finding any reference for 15 degrees or 20 degrees. I've only been looking in the IBC so far so perhaps that's the issue, but if you have any other reference that could point me to up to 20 degrees being acceptable, I'd very much appreciate it! Thank you!

Steve

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Yep. A ramp that receives only deliveries still needs to be safe.

In general the place where we see steps and rails not being required to meet common safety standards is where they are giving access to special areas such as a confined attic space housing a heat pump or A/C unit - entered only rarely and then by just a service technician. A ramp at a business is going to see more traffic than that, not to mention the increased risk of a fall when the FedEx or USP drivers RUN up and down the ramp (in my experience they never walk) or when she is pushing a hand-truck piled so high with boxes that she can't see the edge of the walkway. OPINION: I'd make it as safe and strong as possible. And as required. You can read Ohio's access ramp codes under the OH accessibilty law at https://www.com.ohio.gov/documents/dico_August292014BuildingontheCodeAccessibility.pdf though I agree "accessabilty" for people of limited mobility isn't the same population as delivery truck operators. What if the ramp is only for deliveries? ie… FedEx or UPS. Do the same standards apply at a business in Ohio? Currently all deliveries come thru our front door because we only have stairs at our loading dock. I am designing a raised patio to replace the current stairs and thought about adding a ramp. Thank you for your help.

Wendy,

I can help with researching and answering specific questions, but to be clear, ​​We do not sell anything.

InspectAPedia provides building and environmental diagnostic and repair information.

In order to absolutely assure our readers that we write and report without bias we do not sell any products nor do we have any business or financial relationships that could create such conflicts of interest. InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information for the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website. We very much welcome critique, questions, or content suggestions for our web articles. I live in Wharton, Texas and amdisabled getting in and out of my home is a nighmare can you please help me? I would appreciate any assistance you can provide.

Thank You,

Wendy Eplen

Wendy Eplen

416 Croom Drive

Wharton, Texas 77488

phone: (979) 282-1846

email: wmeplen.h@gmail.com

Question: what is the correct number for permitted ramp slope in degrees?

2020/04/20 Luke said:

The "bottom line" section above says "the preferred slope for a building access ramp is between 7 and 18 degrees, and permitted slopes range between 0 and 20 degrees." However, I'm having difficulty finding any reference for 15 degrees or 20 degrees. I've only been looking in the IBC so far so perhaps that's the issue, but if you have any other reference that could point me to up to 20 degrees being acceptable, I'd very much appreciate it! Thank you!

Moderator reply:

Luke

Thank you for pointing out an error in our original text. I've reviewed and corrected and clarified the question of allowable ramp slope on this page. The "20" in the text above is correctly written as a slope of 1 in 20, also written as 1:20 or 1 inch of vertical rise in 20 inches of horizontal run.

I'm editing the text to be sure it's clear.

We are NOT talking about a 20 degree angle of slope.

Maximum Egress Ramp Slope = 1:12 slope = 8.33% slope = a 4.76° degree slope Other Ramps Maximum Slope = 1:8 slope = 1.5:12 slope = 12.5% slope = 7.13° slope Typically in sketches and plans like the drawing we show above where common ramp slopes are in the orange area, ramp slopes range between 0° and 18° with a preferred slope of about 7° or 1.5:12 or by the 2018 IRC Ramp Code, a more-gentle slope of about 5° or 1:12.

2018 IRC Ramp Code - Maximum Slope

R311.8 Ramps.

R311.8.1 Maximum [Ramp] slope.

Ramps serving the egress door required by Section R311.2 shall have a slope of not more than 1 unit vertical in 12 units horizontal (8.3-percent slope). All other ramps shall have a maximum slope of 1 unit vertical in 8 units horizontal (12.5 percent). Exception: Where it is technically infeasible to comply because of site constraints, ramps shall have a slope of not more than 1 unit vertical in 8 units horizontal (12.5 percent). - Source: IRC as adopted by the City of Los Angeles, cited as Los Angeles Residential Code, 3 Building Planning, R311 Means of Egress , R311.8 Ramps , R311.8.1 Maximum slope (2020/05/01)

Notes about How to Calculate Slope or Rise:Run Angle or Percent

Slope in Rise / Run x 100 = Slope in Percent

Slope in Degrees = Tan-1 (Slope Percent/100)

A 1:12 slope (rise over run) has a percentage slope of 8.33 % that, converted to degrees is: 4.76° of slope A 1.5:12 slope (rise over run) has a percentage slope of 12.5 % that, converted to degrees is: 7.13° of slope

Synonyms for slope include pitch, angle, rise, incline, or grade.

To see details of converting percent slope to degrees of slope

see CONVERT ROOF SLOPE or ANGLE in DEGREES to RISE - that pertains to ramps and stairs as well

Also

...

Continue reading at RAMP SLIP TRIP FALL HAZARDS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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