NAAMM AMP 521-12
Pipe Railing Systems Manual
My recommended reading list has several NAAMM specifications listed. Here are the key points from my reading of the NAAMM Pipe Railing Systems Manual. Click here for the free download link from NAAMM (50 pages).
All notes are paraphrases or snippets and quotes from larger sections. I suggest reading the entire manual to get familiar with the requirements of this standard.
The information in this manual represents recommendations from manufacturers of pipe railing systems and suppliers of component parts.
NAAMM’s primary objective is to encourage efficient designs that comply with recognized standards of performance for all architectural metal work. See page 7 for four sample types of joint construction.
Galvanized railings should be either hot-dip galvanized or fabricated from galvanized pipe with zinc-rich paint applied over welds and abrasions.
Railing System Materials
Pipe sizes are given in nominal Iron Pipe Size (IPS), the actual OD is greater than the nominal IPS. Tubing sizes are given in actual OD and wall thickness.
Fabrication of railing has become more labor intensive with increased restrictions in allowable size openings. A large percentage of cost is from grinding and sanding to dress each welded joint.
Depending on use of the railing, desired appearance of the joints varies considerably.
The main difference between pipe and tube is in dimensional tolerances and surface qualities.
Tube tolerances are closer than pipe tolerances and have a smoother surface.
Tube-quality is used when an etched, anodized or polished finished is required.
6061-T6 is not suitable for pending and has a yellowish tint when anodized.
Alloy 5053 filler wire is used to minimize discoloration if an assembly is to be anodized.
If appearance is important welds are ground, polished and blended; otherwise, as in structural applications, welds are left untouched.
Welding removes temper and reduces strength within 1” of a weld.
Table of types of anodic coatings for Class I and Class II.
Welded stainless steel mechanical tubing is available in the same outside diameters as stainless steel pipe, but at lower cost.
Care must be taken in fabricating, finishing and maintaining stainless steel to avoid contamination.
Railing System Joint Construction
- Type 1 – Ornamental Quality, used where appearance is a critical factor
- Type 2 – Weld of good appearance used in areas of traffic, where highly ornamental quality is not required
- Type 3 – Used in areas where it is not subject to view, as in service stairs
- Type 4 – Acceptable when appearance is not a factor, used in industrial and non-public areas
The photograph examples contained here are a valuable resource to reference to ensure fabricators and designers are on the same page regarding expectations of finish quality. Whenever a drawing says “smooth” the fabricator should ask during the bidding process which type of smoothness is being specified.
A guardrail system is defined as a vertical protective barrier erected along exposed edges of stairways, balconies, etc.
Guardrail systems are typically designed to withstand significantly higher loads than railing systems.
Where rail is laterally braced by a change in direction or attachment to other structure, bending moment in posts may be reduced significantly.
The purpose of design regulations is to insure that railings systems provide protection against persons falling, and the railing system need not remain in perfect alignment to perform this function.
If rail size is inadequate, either the post spacing shall be reduced or the size of the rail and posts shall be increased.
This section contains several pages of design calculation methods for various railing material types and configurations. Useful for engineers but not a lot of practical help on the project management level.
Installation and Anchorage
Performance and safety of pipe railing systems are determined primarily by: structural design, fabrication and installation.
Where water can enter posts in outdoor applications, weep holes shall be provided at their lower ends to provide drainage.
Anchor holes shall be drilled no closer than five (5) hole diameters from the edge of concrete or masonry.
Pipe and Tube Dimensions and Properties
Charts containing product data on pipe and tube including figures for section modulus and moment of inertia.
Contains a sample specification section for specifiers with notes.
Glossary of Terms
Terms commonly used in the pipe railing system industry.
Useful for training and new hires, reading this will shorten the learning curve for anyone new to the industry
Hope you found this helpful. Take a look at my recommended reading list for links to additional resources, most of which are available for free.