Are You Aware of the Load Requirements for your Railing Installations?
A Deeper Look at Structural Requirements for Handrails and Guards
Fabricators installing railing systems need to meet structural requirements and ensure compliance. This is becoming a bigger issue since imports don’t always meet the same requirements. This is all the more important with trends towards the use of heavier glass and less metal. With the International Building Code (IBC 2015) as the standard building code model, codes go beyond dimensional requirements for handrails and guards. They are really focusing on creating a safe environment.
While most people in the railing business are familiar with the dimensional requirements set forth by IBC 2015, the structural requirements are equally important and must be considered when designing, specifying, and installing a railing system.
IBC 2015 Load Requirements
The IBC 2015 refers to load requirements in several sections. The following have special bearing on handrails and guards:
- 8.1 Handrails and guards. Handrail assemblies and guards shall be designed to resist a linear load of 50 pounds per linear foot (plf) (0.73 kN/m) in accordance with Section 4.5.1 of ASCE (American Society of Civil Engineers) 7. . .
- 8.1.1 Concentrated Load. Handrails and guards shall designed to resist a concentrated load of 200 pounds (0.89kN), in accordance with Section 4.5.1 of ASCE 7.
Per ASCE7, the load specified must be placed at the “top” of the handrail or guard.
Deflection, although a common concern, is not usually defined in building codes. It is touched upon indirectly in IBC Section 1604.3, which addresses the serviceability requirements of structural members in general:
- IBC 1604.3 Serviceability Structural systems and members thereof shall be designed to have adequate stiffness to limit deflection and lateral drift.
While a building inspector can confirm the dimensional requirements for handrails and guards – minimum height, handrail graspability, and opening limitations – confirming the structural integrity is not possible without physical testing or calculations. Guard and handrail performance testing and calculations are typically based on:
- Material selection and size
- The span – post or handrail bracket spacing
- Wall or floor attachment
- Load distribution (the load applied to the top which is distributed along the railing)
Material Selection Implications
Choosing the type of metal – aluminum, steel, or stainless steel – is commonly the first step when designing a railing system. While selection may be based upon a number of factors including aesthetics or costs, it’s important to consider the implications of material selection for load requirements as well.
Painted steel will not perform as well in an exterior application but it will be stronger and less expensive than an aluminum railing. However, aluminum systems may require smaller spans or reinforcing inserts to meet the load requirements.
For example, in a post-mounted railing system, the posts are the critical components for load bearing ability and appearance can be misleading. A standard 1-1/2” nominal pipe size post (1.90” actual diameter) is a good choice for posts but outside diameter is not enough – the wall thickness will provide the strength needed to meet the IBC. Thinner wall posts = less material = less cost = poor performance.
Most imported railings systems are provided with a .050” or .083” wall. Load requirements will be better served with 1-1/2” schedule 40 pipe size (1.90” diameter with a .145” wall).
On paper, post spacing is a function of the minimum yield for design of the material, the load requirement, the height and the section modulus. The section modulus for 1.9” diameter with a .083” wall thickness is .206 cubic inches while for 1.9” diameter with a .145” wall thickness, it is .309 cubic inches.
Attachment is another area of concern in railings as it relates to load requirements. Any wall or surface mounted railing system will only be as strong as the fasteners and the structure to which it is attached. Select the proper anchor for mounting to concrete; or attach to wall studs or provide backing for wall mount brackets.
Lacking the ability to field test a handrail or guard, building inspectors will expect that the installer/fabricator provide support data – calculations or test results – supporting the use of your railing system. The best bet is thus to confirm with your supplier or an engineer to determine what is appropriate for your application.
Glass Railing Specific Requirements
The 2015 IBC additionally has load bearing requirements specific to glass railings. These are covered in IBC section 2407.
- IBC 2407.1.1 Loads. The panels and their support system shall be designed to withstand the loads specified in section 1607.8. A design factor of four shall be used for safety.
- IBC 2407.1.2 Support. Each handrail or guard section shall be supported by a minimum of three glass balusters or shall be otherwise supported to remain in place should one baluster fail. Glass balusters shall not be installed without an attached handrail or guard. Exception – A top rail shall not be required where the glass balusters are laminated glass with two or more glass plies of equal thickness and the same glass type when approved by the building official. The panels shall be designed to withstand the loads specified in Section 1607.8.
In-fill – balusters, cable railing, glass, woven wire, etc. – are required to meet a 25 lb. /sq. ft. load requirement.
Other key elements of section 2407 for glass of the 2015 IBC are:
- Laminated glass shall be used in glass railing systems – structural balustrades and infills.
- Minimum nominal thickness shall be ¼”.
- Glass can be fully tempered laminated or heat-strengthened laminated.
- Laminate must comply with CPSC 16 CRF 1201 Cat II or ANSI Z97.1 Class A.
- Single ply fully tempered glass may be permitted where there is no walking surface beneath the system or if the surface is permanently protected from the risk of failing glass
- The panels and their support systems should be designed to withstand the loads as specified by the code. A design factor of 4 shall be used in designing the glass.
- Top rail is not required if the laminated glass is comprised of two or more glass plies having equal thickness and if the system is approved by the local jurisdiction.
- In windborne debris regions:
- In-fill glass must be laminated and comply with safety glazing standards.
- If the glass is supporting a top rail, the top rail must stay in place after impact and meet the structural requirements.
- Glazing materials shall not be installed as handrails or guards in parking garages – except in pedestrian areas.
Turn to the Experts
Understanding the building code and what it specifies for load requirements is a challenge. It may be an occasional occurrence in your world, but at Wagner we deal with these questions every day. The Wagner Companies team knows what it will take to meet the load requirements and can provide test data on our railing products and guide you in navigating the building codes.
In the end, it’s not just about the transaction but about the relationship between you and your supplier. Contact us for more information.
The Wagner Companies focus is providing great parts, on time. With over 60 years of manufacturing experience in Milwaukee, our engineering, stamping, bending, welding, polishing, press brake, and laser operations are ready to meet your needs. Send us a request for quote on your project and let us introduce you to the world of The Wagner Companies. Download our Code Guide.
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Byline: Tony Leto is Executive Vice President (Emeritus) at The Wagner Companies. He has been in the metal business since 1984 with particular expertise in the areas of handrails, guards, building codes, and standards.