Prior to using any railing products, it is incumbent on designers, fabricators and installers to make themselves familiar with local codes that apply to their applications.
Most municipalities and local code bodies do not write code – they adopt codes prepared by various code bodies. Historically, model codes were prepared by code bodies such as the Building Officials Code Administrators International, Inc. (BOCA), the Council of American Building Officials (CABO), the International Conference of Building Officials (ICBO), and the Southern Building Code Congress International (SBCCI). Others codes often referred to include the Occupational Safety and Health Administration (OSHA), the National Fire Protection Association (NFPA), and the Americans With Disabilities Act Accessibility Guidelines (ADAAG).
Prior to 2000, BOCA, SBCCI and ICBO each prepared their own model codes that were regionally applied. In 1999, these three organizations began to work together to prepare a unified code under the auspices of the International Code Council (ICC). The first set of I Codes were published in 2000 and included the International Residential Code (IRC) and the International Building Code (IBC). The 2000 IRC and IBC model codes have since been adopted by states throughout the country. The "I" Codes are published on a three year cycle.
Consult your local authorities to see what codes apply to your project.
The NFPA has chosen to enter the building code arena. with the creation of NFPA 5000. This has not been widely adopted however, provisions of NFPA 5000 have been incorporated into NFPA 101 -- Life Safety Code. Some conflicts -- in particular is it relates to clearance between a handrail and wall exist. Confirm with your local officials when specifying.
Handrail and Guard
Handrails are in place to provide guidance while the purpose of a guardrail is to prevent accidental falls.
Guards are generally required for ramps, stairs or landings above 30". The height will vary depending on the code. The IBC requires a guard to be 42" in height. Handrails are located between 34" and 38" and have dimensional limitations for graspability. As such, if a 42" guardrail is called for on a stair or ramp, it will also require a secondary handrail at the appropriate height. A guard top rail that is not used as a handrail would not have a graspability size limitation.
Guards also have opening limitations to consider. The most common requirement is that no opening be large enough to allow a 4" sphere to pass.
While a handrail may need to be installed on stairs less than 30" high, it does not have to meet the opening limitations required of guardrails. This is often being misinterpreted by local inspectors who have insisted on applying guard requirements to these applications.
Refer to the accessibility page regarding similar height standards on accessible railing and the Access Board’s recommendation for railing for children.
The Ladder Effect
The published 2000 IRC stated that guardrails shall not be constructed with horizontal members or other ornamental pattern that results in a ladder effect. The ladder effect has never been a part of the IBC.
The ladder effect was removed from the IRC during the 2001 code cycle. The change was noted in the 2001 IRC supplement and it is not in the 2003, 2006 or 2009 IRC. It has never been in the IBC.
However, many local code authorities are using older codes based on BOCA – the creator of the ladder effect wording – and the 2000 IRC. Many local code inspectors are not aware of the 2001 change and may reject guards with infills they interpret as creating a ladder effect.