Building Code Questions - Titan Post Anchor
Will the 4x4 Titan Post Anchor work with the Building Code?
This is a great question we get all the time.And there seems to be a lot of confusion out there among people about how to build wood railings that will meet the building code requirements.
The answer to that question is both Yes and No.
Reading the following questions and answers will help you understand this issue better.
- Is the post anchor "approved" by the building code?
- What does "approved" mean?
- Why is the post anchor not "approved" by the building code?
- Has the 4x4 Titan Post Anchor been tested by an independent lab?
- Why did you only test a single unsupported post?
- How did you set up this test?
- What were the results of the test?
- Can I see the test report?
- Can I build a wood railing system with the post anchor that will meet the building code?
- How high does a guard rail have to be?
- How much lateral force along the top rail must a guard rail system withstand?
- What is a guard rail as opposed to just a railing?
- How does post spacing affect the strength of a railing?
- Can I connect the post anchor directly to deck boards?
Is the post anchor "approved" by the building code?
No. At least not yet - And that is because there is no ICC-ES number or report because it is a component - not a system. ICC-ES reports however can be obtained for complete railing systems such as the composite systems you see on the market. What we are in the process of doing is taking those same testing standards (AC 273 used for testing composite railing systems) for a "railing system" and testing the post anchor first as a single unsupported post and then in a series of post and rail sections to complete our program.
So we have embarked on a comprehensive engineering testing program for 2010 by the experienced firm Intertek. The first results have just come in but there are many more tests which will be done over the coming months. As of March 1, 2010 a 42" pine 6x6 post, based on testing three samples, had an average load to failure of 503 lbs and a 4x4 42 pine post had an average load to failure of 336 lbs.
Based on this test alone, the 6x6 post anchor passes the highest testing standards used in AC 273 for actual post and rail installations and this was just a single unsupported post. The 4x4 post does not yet meet that test (500 lbs point load) but that does not mean that when used in a complete railing system the finished system will not meet those standards. Further testing is being done and we will be reporting it as it becomes available. Based on this first initial series of tests to isolate the perforance of a single anchor and post, we can say based on independent accurate testing techniques that the anchor itself is a high performer.
What we will end up with is a series of data points on load ratings for a 42" wood post by itelf, as a corner post or directional change and as a terminal post with a post brace. With these three load ratings it will be possible to add up the corresponding loads of each post type in any given run of rail and see what the total load is and compare it to the uniform design load of 50 lbs per foot of rail. This will be very useful and essentially answer any question if you are using it in a building code application.
Here is when the building code applies for guard rails:
If a railing system is 30" (24" in Canada) or more above grade the building code for guard rails will apply and the railing system must meet minimum point loads and sustained loads along the top rail and certain dimensional requirements.
A railing system can be made up of many components such as wood posts, metal posts, balusters, top and bottom rails, screws, nails, bolts, glass panels, wire, top and bottom rail connectors, post anchors and more.
What does "approved" mean?
People get this confused a lot. Approved means that the product by itself meets standards set out in document prepared by the International Code Council (ICC) for that very product. But when certain products are mere components of a system and the ICC has written standards for that system, then you have to build the corresponding system with the product as a component of the system.
If the system meets the standard, the system receives approval - but not necessarily the products that are components to the system. So it gets a bit complicated and misleading to say a product is approved.
There are two organizations in the US and Canada that building product companies can submit their product to, if they choose, and ask them to conduct specific tests on the product when it is used in very specific ways.
These organizations provide their opinion on whether a construction product or system complies with the requirements of the building codes either as an acceptable solution or an alternative solution or a combination of both. Acceptable solutions are those that comply with the code's applicable requirements.
The biggest organization is the ICC in the US and the Canadian Construction Materials Centre (CCMC) in Canada.
The post anchor would fall under the category of testing a "system" which is made up of other components and building materials. So it depends on how the "system" is built that determines whether the resulting "system" complies with the building code, of which the post anchor would only be a single part.
These organizations are more than willing to conduct various tests on various systems constructed in as many different ways possible. Their basic testing services, technical reporting plans and related services can easily surpass $20,000 in Canada and as much as $50,000 or more in the US.
We have committed to an extensive engineering program for 2010 which will test the product by first isolating it and then testing it when used in a specific railing construction method so that people can make an apples to apples comparison of it against the ICC standards.
Why is the post anchor not "approved" by the building code?
Railing systems can be built in many different ways - proper or improper. For example if someone spaces wood posts at 10 feet apart there is almost no way the resultant railing system will withstand the minimum point loads for a guard rail application. So it is not the post anchor itself which needs to be "approved", it is the way in which a railing system is built with the product that matters.
The post anchor as it currently exists solves a big problem for a large number of people. That is to say it provides one of the very best combinations of strength, post longevity, improved appearance because of the internal anchoring mechanism and ease and speed of installation.
However, it is not a "silver bullet".
It is not all things to all people. But, what it does is marry strength and great aesthetics very well.
R&D is a huge component of Titan Building Products and we are continually developing and testing new designs which will inevitable continue to raise the performance level of the product. You will see these results posted on our website as they emerge.
When we complete our engineering program in 2010 we will have a table showing the individual loads for certain types of post configurations so that people can refer to this as they build their own rail systems. By adding up the total loads it will be easy to determine if the proposed railing surpasses that prescribed by a building code.
Has the 4x4 Titan Post Anchor been tested by an independent lab?
Yes. We have hired Intertek, a engineering firm steeped in experience in these matters to determine what kind of loads the post anchor can handle using a 42" unsupported post.
Our first series of tests in January 2010 were designed to isolate the strength of the 6x6 and 4x4 post anchors when used with 42" unsupported pressure treated pine posts. Tests were administered on three samples of each combination. The 6x6 anchor and post rated an average load before failure of 503 lbs and the 4x4 rated and average of 336 lbs.
We are now in the second phase of testing and will be reporting these as they become available.
In addition, we continue to test new prototypes and designs which will continually be posted on this site as time goes on.
Why did you only test a single unsupported post?
There are many different ways in which wood railings and combinations of wood and other component materials such as iron, aluminum, vinyl and fiberglass can be used together to create a railing system. Each test is expensive to conduct and the test result speaks only to that specific combination of materials and configuration.
Our engineers recommended starting any tests first by focusing on the product. We wanted to know with as much confidence as possible how the specific component (the post anchor and resulting wood post connection) would perform when isolated outside of a railing system. This would allow us to understand the characteristics of this single part of a wood railing system and allow users to reasonably extrapolate or determine how a railing system using it would perform.
The post anchor is but one element of many others which in combination work to create a railing system that may, depending on the elevation of the deck be subject to the building code standards.
After gathering all the test data it will be possible to construct a table showing the various load ratings in certain situations which will be useful to the greatest number of people.
How did you set up this test?
They administered a horizontal load at the 42" height of a 4x4 and 6x6 post connected to a fixed point at the base and measured the force required to pull out the bolts from the post and develop a crack in the wood.
This was not a test for a railing system but rather a test to isolate the performance of the post and anchor working together outside of a railing.
According to the Acceptance Criteria of Handrails and Guards - AC273/ASTM D 7032 three different tests are applied. One of these tests is a concentrated load test which is applied at critical locations; top rail mid span between posts, top rail adjacent to a post and top of a single post at the end of a railing span. Deflection is measured once the applied load reaches 200 lbf and post/rail movement must be within certain maximum limits based on post spacing or rail length and post height.
But since this test was for a single post only it was actually a higher standard to achieve but it was necessary to begin our testing from this point. The 6x6 already passed this test as a single post. Quite impressive. But the testing procedure calls for an actual post-rail-post section to undergo the test with top rail loads at midspan, near endpost and endpost load.
Our next phase of testing will encompass this exact type of testing.
What were the results of the test?
A single unsupported 42" 6x6 wood post required an average of 503 lbs to cause failure in the post. For a 4x4 42" post an average load of 336 lbs was required to cause failure. Three samples are tested. The test results for the 6x6 ranged from 560 lbs, 450 lbs to 510 lbs. For the 4x4 the test results ranged from 400 lbs, 300 lbs and 310 lbs.
Can I see the test report?
Yes. Contact us and we will send you a copy.
Can I build a wood railing system with the post anchor that will meet the building code?
It certainly is possible and it depends on the length of the run of railing between directional changes or an end post. We have a post brace that when installed properly bumps the performance of our single 4x4 post and anchor up to around 600 lbs. So between the combined load ratings of a corner post/directional change, intermediate post and terminal post with a post brace the minimum code standards can be surpassed.
But we do not at this time provide guidance as to how you should construct your railing. Once our testing program is complete we will be in a position to provide this kind of direction based on a specific railing construction technique that our testing will be based upon.
Until this time we advise that you consult your local building authority or engineer to determine if your wood railings are subject to the building code and if so, whether your designs will be acceptable.
How high does a guard rail have to be?
Guard rails must be at least 36" high if the surface is 30" above grade. In some other instances they must be 42" high. Any railing that is less than 30" above grade does not have to meet the guard rail standards in the building code.
California changed their building code so that any guard rail 30" or more above grade must be 42" high. This is the only state that prohibits 36" railings.
You should obtain a copy of your applicable building code to ensure that these stipulations above are still valid as codes to change from time to time.
How much lateral force along the top rail must a guard rail system withstand?
A guard rail system must withstand a 200 lbf concentrated load at any point along the top rail. This value is 225 lbs in Canada as they use a metric value (1.0KN). Safety factors are also applied in different jurisdictions and can range from 1.5 to 2.5 for testing purposes. A 42" high railing will experience greater leverage than a 36" high railing.
A guard rail system must also withstand a uniform load of 50 plf (125 plf if you apply a 2.5x safety factor) applied vertically and horizontally along the top rail. You should consult your local building authority or engineer if you any doubt about your particular railing in question.
What is a guard rail as opposed to just a railing?
All guard rails are railing systems but not all railing systems are guard rails. To be a guard rail the railing system must be used in situations where the deck surface is 30" or more above grade and must meet the minimum requirements as stated in the building code.
How does post spacing affect the strength of a railing?
When force is exerted against a railing it is distributed to the various components of the railing system; the posts, the balusters and railing sections, the top and bottom rails and the deck surface and joist structure below.
A railing system is made up of a plurality of posts and railing sections connected between each post. Each post shares a percentage of the load against the railing system. The more posts over a specific distance and the more rigid the railing sections between the posts, the less force each post absorbs and thus the stronger the railing system.
The stronger a single post is in its overall role and function within a railing system, the farther apart these posts can be spaced and still provide a certain degree of lateral resistance. If weaker posts are used, they may be spaced closer together in order to increase the resultant strength of the railing system and thus potentially still meet the minimum code requirements.
Can I connect the post anchor directly to deck boards?
Yes. However the post to deck connection is only as strong as the deck boards. Blocking should be placed under the deck boards so the fasteners have more material to connect to.