Current IBC® and IRC® codes require guard rails to withstand a lateral load of 200 pounds, applied 36 inches above the nose of the stringer. This isn’t adequate protection for your stair railings or you. Imagine having a group of people on your deck stairs and someone trips and falls against the railing. Imagine if it were a large adult. Imagine if those were aging deck stairs prone to structural weakness anyway.
A newly redesigned adjustable stair bracket provides an innovative solution to this stair rail safety concern. It was designed specifically for stair construction and code compliant rail post support. The standard stair bracket was modified and tested for lateral load stair rail post support for cut stringers, angle stringers and for other applications. In more than twelve individual tests, all brackets withstood a load of 500 pounds applied 42 inches above the nose of the tread (an IBC requirement for non-residential applications), with some tests approaching 600 pounds before failure.
The National Safety Council shows slips and falls on stairs, result in 2,000 fatalities each year, making stairs the most dangerous area of the home. Once the hand grip or hand rail becomes unstable, safety is greatly compromised. This is particularly evident with persons over age 65. NSC statistics show that the leading cause of death and serious injuries for persons over age 65 are slips and falls.”
Secure hand and guardrails are critical for stair safety and there are many viable solutions for securing handrails. Unfortunately, this is not always the case for guardrails, specifically when they are attached to wood stairs. Guardrails are normally secured to rail post supports, which in turn are attached to a stringer. Some within the building industry have expressed concern that the standard installation methods used for rail post attachment fall short of meeting the lateral load capacity required by code. Products, such as the bracket evaluated in ICC-ES’s report for code officials and professionals in the construction industry: ESR-2295, helps ensure that current and future construction meets this requirement.
How do most code officials tend to test stair rail safety? Far too often, it’s a ‘tug and bump-the-rail’ test and if it seems solid, it passes. In some traditional construction, stairs are built with three or more cut stringers. Stairs may have both risers and treads, or treads only. The guardrail is normally 36 inches high for residential construction and is secured via posts bolted to the cut stringers. Often, the rails themselves are strong enough to meet code, but the attachment of the post to the stringer is the weak link.
An IAS accredited testing facility was engaged to test the load capacity of this traditional construction practice. A stair was constructed, with three 2×12 cut stringers and two 2×6 members for each tread, using dry, #2 Douglas Fir. Three 48-inch-long posts were attached using two 3/8-inch galvanized bolts. The top bolt was attached through the triangular cut portion of the stringer (normal practice) and the bottom bolt passed through the uncut portion of the stringer. A 3/8-inch eye bolt was attached 36 inches above the nose of the tread as the load point. The load was applied to each post and measured using a dynamometer. In each case, the bolt pulled through the cut, triangular rise/tread tip of the stringer at a load of just 20 pounds. As the load was increased to 50 pounds, severe longitudinal cracks were seen along the length of the stringers, breaking all triangular tips and resulting in complete failure of both the stringer and the rail post support.
All three tests consistently showed significant structural failure occurring at minimal loads and several reasons for the early failure were identified. The post acted as a lever against the stringer, magnifying the load on each bolt. A 20-pound pull at the guardrail level resulted in a 120-pound force at the base of the post and caused the top bolt to pull through the stringer. Once the top bolt had broken through, the bottom bolt was left to resist the entire load. The mechanical advantage was further amplified by the lower position of the bottom bolt, and the final 50-pound pull on the guard rail became a 1,200-pound force at the base. This was enough to twist the stringer and cause it to crack longitudinally. The tests were conducted on isolated posts without railing. Often, a continuous rail is used, which can help to distribute the load to other posts, decreasing the load effects on the bolts at a single post attachment. However, the test was designed for worst case scenarios, which were correctly reflected in the above testing.” Guardrail failure is unnecessary and the consequences can be tragic.
The new ICC-ES evaluated EZ Stairs® rail post attachment technology which affords a simple and efficient, code compliant solution to this very serious issue.
Look up report ICC-ESR 2295.
EZ Stairs® has been voted ‘Hot Product’ of the year at the International Builder’s Show over and over. The system has won awards for innovation in the construction industry. It is the only adjustable bracket system anywhere and can be used to meet all building codes for any interior or exterior (deck stairs, wood stairs and concrete formwork stairs) application and can now double as a code compliant rail post support attachment ICC-ESR 2295. See a 3D video demo of how it works.