- Page 27 of 50 - News, Notes and Discussion from the Simpson Strong-Tie Engineering Department

How to Pick a Connector Series: Selecting a Joist Hanger

A quick glance through the Simpson Strong-Tie® Wood Construction Connectors catalog shows that we manufacture at least 29 different models of face-mount wood-to-wood joist hangers, three separate models of face-mount wood-to-masonry hangers, 42 different models of top-flange wood-to-wood joist hangers, four different models of top-flange wood-to-masonry hangers and 15 models of specialty joist hangers. And that’s not even counting heavy truss girder hangers or multiple- member hangers. So it’s no wonder that sometimes it’s difficult to pick exactly the right hanger for your particular application.

There are many things to consider when picking a joist hanger. The first may be what your load requirements are, including their direction. That will sometimes determine the second consideration. Do you want to use a top-flange or a face-mount joist hanger? Top-flange hangers typically have higher down loads with fewer fasteners, but must be installed when there is access to the top of the supporting member and often before the joist is in place. On the other hand, face-mount hangers can be installed after the joist is in place, and can have higher uplift loads, but will use more fasteners.

Speaking of fasteners, any fastener preference can determine your selection of a hanger. Joist hangers can be installed with common nails, screws (SD for lighter hangers and SDS for heavier hangers), or even bolts, for heavy glulam hangers. See here for information on the various fasteners that can be used with our connectors. The Simpson Strong-Tie Wood Construction Connectors catalog does not list allowable loads for joist hangers installed with SD screws, but you can find them here; just click on the link of the product to find its allowable load. Also, if the joist hanger will be installed with pneumatic fasteners, we have a Technical Bulletin on the possible load reductions that will result.

Another thing to consider at the beginning is what types and sizes of members are being connected together. Is your connection all solid-sawn dimension lumber, engineered wood or structural composite lumber, glulam beams, or trusses? All these types of wood products require different hangers.

Furthermore, joist hangers will have different capacities based on the species of wood to which they are being attached. For example, the truss hangers in the table below have allowable loads listed for Douglas Fir-Larch, Southern Pine and Spruce-Pine-Fir/Hem Fir. Most standard solid-sawn joist hangers, on the other hand, will only have two load ratings, DF/SP and SPF.

Top-flange hangers are sensitive both to the species of wood and to the type of engineered wood to which they are attached. Because of that sensitivity, they have to be tested to each different type of engineered wood that could be used as a header and may have different published allowable loads for each type as shown here.

Is the joist framing into the side or top of a concrete/masonry wall? Then a special joist hanger is required. Is the joist connecting to a nailer on top of a steel beam or concrete/masonry wall? Nailers require top-flange hangers and can result in loss of allowable load if you have to use shorter nails, so you need to check that carefully. There are special tables published for nailer loads for top-flange hangers.

Another consideration is the orientation of the members. In a perfect world, all connections will be between perfectly perpendicular members. But in the real world, joists may be rotated side to side (skewed), or up or down (sloped), or some combination of the two. There are a couple of options in those cases. Hangers such as the SUR/SUL series are available pre-skewed at 45 degrees. Adjustable hangers such as the LSU/LSSU series can be adjusted within limits to certain slopes, skews and slope/skew combinations. Simpson Strong-Tie also has the capability to custom-manufacture quite a few types of hangers to any slope or skew within certain limits, based on the hanger. All of these options, including any load reductions required, are listed in the Hanger Options section of the catalog or website. The table there gives the various options available for each product and clicking on an individual hanger in the website table will send you to a page with the specific reductions for each option.

Another important consideration is the installed cost of the joist hanger. Simpson Strong-Tie publishes what we call an Installed Cost Index, where the total installed cost of a hanger, including fasteners and labor, can be compared for related hangers. For example, there are six joist hangers listed in the Solid Sawn section for a 2×6 joist. They are listed in order of increasing Installed Cost Index. To choose one, simply find the one with the lowest installed cost that meets your load requirements.

Obviously, this is a lot to think about when trying to choose a simple joist hanger. In order to make choosing a connector as easy as possible for our customers, Simpson Strong-Tie offers two different software tools to help. The first is our old standby, the downloadable Connector Selector. This is a versatile program that will help the user pick a joist hanger, truss hanger, multi-truss hanger, column base, column cap, holdown, mudsill anchor, hurricane tie, multi-ply lumber fastener, embedded anchor bolt or hinge connector. It can be downloaded from here. You can see from this example that the Connector Selector gives several options for nailing of joist hangers that may not be directly listed in the catalog.

For a quick aid in choosing a connector, Simpson Strong-Tie recently developed our Joist Hanger Selector Web App. This is found directly on the strongtie.com website. While not necessarily as versatile as the Connector Selector, it has a much easier-to-use graphic interface where the user can choose any option they wish. Just simply choose the desired hanger type, the header member, the joist member, the fastener type, any hanger options and input any design load requirements, then hit calculate, and your choices show up immediately.

Here is the output shown for the same inputs as the Connector Selector above. The app will initially show only the most common models that provide a solution, but the user can click SHOW ALL MODELS for a more complete list of solutions. The user can also click on the “+” next to the model name to get additional fastener options.

A final consideration in choosing a joist hanger is the finish desired. Simpson Strong-Tie manufactures joist hangers in several different finishes: Standard G90 zinc coating, ZMax® G185 zinc coating, HDG hot-dipped galvanization after fabrication, Type 316L stainless steel and powder-coat painted. The environment where the joist hanger will be installed and the material it will be in contact with (treated wood or other corrosive materials) will both influence which finish should be chosen. Guidance for selecting finishes is found in our literature and on our website. Also remember that the finish of the fastener used needs to match the finish of the connector.

We hope you find these tools helpful the next time you need to choose a joist hanger. Are there any other tools you need to help you specify Simpson Strong-Tie connectors or anchors? Tell us below.

Facebook Tips for Structural Engineers

In our last social media–related blog post, I shared the Top 5 LinkedIn Groups to Follow for Structural Engineers. Following groups on LinkedIn allows you to share content, post or view job openings, network and help establish yourself as a key opinion leader in your industry. But what about critical design questions or help? How do you deal with office dynamics or a difficult client as a structural engineer?

LinkedIn groups may assist with questions like these, but there are other social media platforms that might make it easier to have a more in-depth discussion about issues that you face. While LinkedIn is certainly an important social media platform for professionals such as structural engineers, it is not the largest social media platform. That title goes to the social media giant Facebook. Facebook has the social advantage of engaging more than 1.7 billion active users.

You are probably using Facebook already for personal social networking. However, there are some professional applications for structural engineers on Facebook that you may not have heard about. Here are some Facebook tips for structural engineers that you can use to jumpstart your professional social media arsenal:

Follow Industry-Related Pages

There are a variety of pages that you can follow on Facebook to give you an idea of what is happening in the industry. Following and engaging with pages like Structural Engineering World for design inspiration or Civil + Structural Engineer magazine for project management ideas allows you to have a more professionally focused newsfeed around content that matters to you (while still allowing time for cat memes and Buzzfeed quizzes if you want those, too). One useful page for engineers is the Autodesk Revit page, because it has things like tips on how to share large BIM files.

Join Structural Engineering Groups

Groups are a great way to connect with other Facebook users. As a structural engineer, you are bound to come across an issue that you would like some advice on. By joining a group of other structural engineers, you can ask design questions, questions about calculations and get tips on the best tools for your profession. I would ask your colleagues which groups they recommend joining.

Jumpstart Your Job Search

If you are looking for a new position, I am sure that you already know about LinkedIn. But did you know that there are things like the Career Center App on Facebook pages like the ASCE? The app works for employers looking to hire, too!

Do you have Facebook tips that would you recommend for structural engineer? Let us know in the comments below.

Screw Substitution Calculator Web App

At Simpson Strong-Tie, we do our best to offer tools that make your job easier. One such tool is the Screw Substitution Calculator. It’s a quick and easy-to-use web app created to help you calculate and design using Simpson Strong-Tie fasteners. The app can be used in two ways: (1) to design for a given load and (2) to provide a substitution for NDS fasteners. The app covers design for withdrawal loading, lateral loading and multi-ply connections. For each of these applications you can either design for a load or input the specified NDS fasteners and design an alternate Simpson Strong-Tie screw substitution. The app can generate detailed calculations in a PDF format for any of the selections made, and these calculations can be used for submittals.

Note that although the tool currently does not address corrosion issues, corrosion resistance should be an important consideration before selecting screws for your application.

Below is a screenshot of the Screw Substitution Calculator. As explained above, the app can design for

Withdrawal Loading
Lateral Loading
Multi-Ply Connections

The input sections for Withdrawal Loading and Lateral Loading (parallel or perpendicular to grain) are similar. A screenshot of Lateral Load Parallel to Grain is shown below.

Step 1: General Information – In this section, you are requested to select either Fastener Substitution or a Load Entry. If you choose fastener substitution, the app will request in step 4, Fastener Information, that you enter the original fastener design. The fastener substitution calculator will provide Simpson Strong-Tie fastener alternatives for the NDS fasteners. The NDS fasteners covered in this app are bolts, lag screws, wood screws and nails.

If you choose Load Entry, you will notice that the Fastener Information step will disappear and no longer be available for input. Next, select a category from the Design Method section. Available options are Allowable Stress Design (ASD), Load and Resistance Factor Design (LRFD) and Not Specified, if you are not sure of the design method. If the Not Specified option is selected, the design assumes the Load and Resistance Factor Design method, and it further prompts you to answer a few more questions related to Wood Moisture Content, Connection Temperature and End Grain Insertion.

Step 2: Side Member – In this section, all the information regarding the side member is entered. You can either select a species from the drop-down list or enter the specific gravity of the member manually in the text box. The information button lists all the available specific gravities for wood species combinations from NDS. Then enter the (actual, not nominal) thickness of the side member.

Step 3: Main Member – Similar to step 2, enter all information regarding the main member.

Step 4: Fastener Information – If the Fastener Substitution option is selected in step 1, step 4 will require you to enter information about the NDS fasteners used in the initial design. Enter the fastener type (bolt, lag screw, screw or nail), along with its diameter and length. From the fastener option list you can either select one fastener substitute at a time for each NDS fastener or enter the number of rows and the spacing of NDS-designed fasteners to determine Simpson Strong-Tie fastener options and their spacing requirements.

Step 5: Factors – Enter all factors required for designing the connection. Information pertaining to each factor is provided by clicking the information (i) button. You can use this as a guide for entering the factors.

Once all the input is entered, click on the FASTENER SUBSTITUTION OPTIONS button.

Clicking FASTENER SUBSTITUTION OPTIONS reveals the available solutions. As a default, the All Types box is checked under Fastener Type, as shown above. You can refine the solutions by unchecking this box and selecting any of the specific fasteners listed – SDWH TIMBER-HEX Screw solutions, for example. On the right, the available solutions are displayed for selection. When a selection is made, the app displays all the input and output for that solution as shown in the screenshot below. You can also create a PDF copy for any of the solutions by clicking on CREATE PDF button.

For Multi-Ply Connections, the input for side members and main members is combined into Member Information as shown in the screenshot below. Once the input is entered, click the FASTENER SUBSTITUTION OPTIONS button to display results. Similar to withdrawal loading or lateral loading, you can create a PDF copy of the calculations.

Let’s design a 3-ply connection with (3) 2 x 12 DF members for a load of 1,000 plf.

By clicking FASTENER SUBSTITUTION OPTIONS, you can see all the available Simpson Strong-Tie fastener solutions. You can then select any of the options to generate detailed output. A screenshot of the output, solution and information regarding the selected fastener is displayed below. You can create a PDF copy of the solution by clicking the CREATE PDF button.

Now that you know how easy it is to design using our Screw Substitution Calculator, you can start using this tool for your future projects. We welcome your feedback on the features you find useful as well as on how we could make this program better suit your needs. Let us know in the comments below.

How to Select a Connector Series – Holdowns

Keith Cullum started off our “How to Select a Connector” series with Hurricane Ties. This week we will discuss how to select holdowns and tension ties, which are key components in a continuous load path. They are used to resist uplift due to shearwall overturning or wind uplift forces in light-frame construction. In panelized roof construction, holdowns are used to anchor concrete or masonry walls to the roof framing.

Holdowns can be separated in two basic categories – post-installed and cast-in-place. Cast-in-place holdowns like the STHD holdowns or PA purlin anchors are straps that are installed at the time of concrete placement. They are attached with nails to wood framing or with screws to CFS framing. After the concrete has been placed, post-installed holdowns are attached to anchor bolts at the time of wall framing. The attachment to wood framing depends on the type of holdowns selected, with different models using nails, Simpson Strong-Tie® Strong-Drive® SDS Heavy-Duty Connector screws or bolts.

A third type of overturning restraint is our anchor tiedown system (ATS), which is common in multistory construction with large uplift forces. I discussed the system in this blog post.

Given the variety of different holdown types, a common question is, how do you choose one?

For prescriptive designs, such as the IRC portal frame method, the IRC or IBC may require a cast-in-place strap-style holdown. Randy Shackelford did a great write-up on the PFH method in this post.

For engineered designs, a review of the design loads may eliminate some options and help narrow down the selection.

Holdown Type	Maximum Load (lb.)
Cast-in-Place	5,300
Nailed	5,090
SDS Screws	14,445
Bolted	19,070

I like flipping through catalog pages, but our Holdown Selector App is another great tool for selecting a holdown to meet your demand loads. Select cast-in-place or post-installed, enter your demand load and wood species, and the application will list the holdown solutions that work for your application.

The application lists screwed, nailed and bolted solutions that meet the demand load in order of lowest installed cost, allowing the user to select the least expensive option.

Adjustability should be considered when choosing between a cast-in-place and a post-installed holdown. Embedded strap holdowns are economical uplift solutions, but they must be located accurately to align with the wood framing. If the anchor bolt is located incorrectly for a post-installed holdown, raising the holdown up the post can solve many problems. And anchors can be epoxied in place for missing anchor bolts.

We are often asked if you can double the load if you install holdowns on both sides of the post or beam. The answer is yes, and this is addressed in our holdown general notes.

Nailed or screwed holdowns need to be installed such that the fasteners do not interfere with each other. Bolted holdowns do not need to be offset for double-sided applications. Regardless of fastener type, the capacity of the anchorage and the post or beam must be evaluated for the design load.

Once you have selected a holdown for your design, it is critical to select the correct anchor for the demand loads. Luckily, I wrote a blog about Holdown Anchorage Solutions last year. What connector would you like to see covered next in our series? Let us know in the comments below.

Firewalls for Wood Construction

What is a firewall?

A firewall is a term that is used in the construction industry to describe a fire-resistive-rated wall or fire-stop system, which is an element in a building that separates adjacent spaces to prevent the spread of fire and smoke within a building or between separate buildings. A firewall is actually one of three different types of walls that can be used to prevent the spread of fire and smoke.

Types of fire-resistive-rated walls:

The three types of fire-resistive-rated walls are firewalls, fire barriers and fire partitions. They are listed in order from the most stringent requirements to the least. A firewall is a fire-resistive-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall. A fire barrier is a fire-resistive-rated wall assembly of materials designed to restrict the spread of fire which continuity is maintained. A fire partition is a vertical assembly of materials designed to restrict the spread of fire in which openings are protected. Each type has varying requirements and the table below displays some of the differences between them.

What are some of the typical uses of each type of fire-resistive wall?

As the requirements for each type of wall vary, so do the uses. Typical uses of each are as follows:

Firewalls – party walls, exterior walls, interior bearing walls
Fire barriers – shaft enclosures, exit passageways, atriums, occupancy separations
Fire partitions – corridor walls, tenant space walls, sleeping units within the same building

How do you determine whether your wood building design needs a firewall?

The 2012 International Building Code (the IBC, or “the Code” in what follows), which is adopted by most building departments in the United States, is the resource we are using in this discussion. (As a side note, it’s possible your city or county has supplemental requirements, and it is best to contact your local building department for this information up front.)

To determine your fire-resistive wall requirements, review these chapters in the 2012 IBC:

Chapter 3, Identify Occupancy Group – typically Section 310 (“Residential Group”) for wood construction
Chapter 5, Select Construction Type – Section 504, Table 503
Chapter 6, Determine Fire-Resistive Rating Requirements – Table 601, typically Type III wood-constructed buildings require a two-hour fire separation for the exterior bearing walls

What are typical fire-resistive wall designs?

Information for one-hour, two-hour designs, etc. can be found in tables 721.1(2) and 721.1(3) of the Code provide information to obtain designs that meet the rating requirements (in hours) for your building, including the walls and floor/roof systems. The GA-600 is another reference that the Code allows if the design is not proprietary.

How do I know whether the structural attachments I specify for the wall and roof assemblies meet the Code requirement?

Once the wall or floor/roof assembly design is selected, the Designer must ensure that the components of the wall do not reduce the fire rating. The Code requires that products which pierce the membrane of the assemblies at a hollow location undergo a fire test to ensure they meet the requirements of the design. ASTM E814 and ASTM E119 are the standards governing the fire tests for materials and components of the fire-resistive wall. There are several criteria that the component in the assembly must meet: a flame-through criterion, a change-in-temperature criterion and a hose-stream test.

Simpson Strong-Tie has created the DHU hanger for use with typical two-hour fire-resistive walls for wood construction.The DHU hanger has passed the ASTM E814 testing and can be used on a fire-resistive wall of 2×4 or 2×6 constructions and up to two 5/8″ layers of gypsum board. The DHU and DHUTF have both an F (Fire) and a T (Temperature) rating.

The DHU/DHUTF hanger has two options, a face-mount version (DHU) and a top-flange version (DHUTF). The hanger doesn’t require any cuts or openings in the drywall, which ensures reliable performance; no special inspection is required. To install the hanger, gypsum board must first be installed in a double or single layer, at least as deep as the hanger. For installation, apply a two-layer strip of Type X drywall along the top of the wall, making the base layer a wider strip (bottom edge is 12″ or more below the face layer, depending on jurisdiction). Then install ¼” x 3½” Simpson Strong-Tie Strong-Drive® SDS screws through the hanger and into top plates of the wall. Since the hanger is more eccentric than typical, the top plates of the wall must be restrained from rotation. The SSP clip can be used for restraint, but the design may not require it if there is a sufficient amount of resistance already in place, such as sheathing, a bearing wall above, or a party wall as determined by the designer. See the photos and installation illustration below for guidance or visit our website for further information.

How to Select a Connector – Hurricane Tie

When it comes to wood-frame construction, hurricane ties are among the most commonly specified connectors. They play a critical role in a structure’s continuous load path and may be used in a variety of applications, like attaching roof framing members to the supporting wall top plate(s), or tying wall top or bottom plates to the studs. They are most commonly used to resist uplift forces, but depending on regional design and construction practices, hurricane ties may also resist lateral loads that act in- or out-of-plane in relation to the wall.

Simpson Strong-Tie manufactures approximately 20 different models of hurricane ties, not counting twist straps, other clips, or the new fully-threaded SDWC screws often used in the same applications. This assortment of models raises the question, “How do you select the right one?”

In this post, we’ll outline some of the key elements to consider when selecting a hurricane tie for your project.

Demand Load

Let’s start with the obvious one. If your building’s roof trusses have an uplift of 600 lb. at each end, don’t select a hurricane tie with a published capacity of less than 600 lb. It’s also important to consider combined loading if you plan to use the tie to resist both uplift and lateral loads. When the connector is resisting lateral loads, its capacity to resist uplift is reduced. I won’t go into too much detail on this topic since it was covered in a recent blog post, but in lieu of the traditional unity equation shown in Figure 1, certain Simpson Strong-Tie connectors (hurricane ties included) are permitted to use the alternative approach outlined in Figure 2.

Figure 1. Traditional Linear Interaction Equation

hurricane ties alternate applications — Figure 2. Alternate seismic and hurricane tie applications.

What if the tabulated loads in the catalog for a single connector just aren’t enough? Use multiple connectors! An important note on using multiple connectors, though: Using four hurricane ties doesn’t always mean you’ll get 4x the load. Check out the recently updated F-C-HWRCAG16 High Wind-Resistant Construction Application Guide for allowable loads using multiple connectors and for guidance on the proper placement of connectors so as to avoid potential overlap or fastener interference.

Figure 3. Allowable Load Comparison for Single and Multiple H2.5A hurricane tie Connectors — Figure 3. Allowable Load Comparison for Single and Multiple H2.5A Connectors

Figure 4. Proper Placement of (4) H2.5A’s to Avoid Fastener Interference

Dimensional Requirements

While the majority of the hurricane ties that Simpson Strong-Tie offers are one-sided (such as the H2.5A), some are designed so the truss or rafter fits inside a “U” shape design to allow for fastening from both sides (such as the H1). If using the latter, make sure the width of the truss or rafter is suitable for the width of the opening in the hurricane tie. For example, use our new H1.81Z (not the H1Z) for 1¾” wide engineered roof framing members.

Typical H1.81Z hurricane tie Installation — Figure 5. Typical H1.81Z Installation

Figure 5. H2.5A and H1 Hurricane Ties — Figure 6. H2.5A and H1 Hurricane Ties

Additionally, the height of the hurricane tie and the wood members being attached should be compatible. For example, an H2.5A would not be compatible with a roof truss configured with only a nominal 2×4 bottom chord over the plate since the two upper nail holes in the H2.5A will miss the 2×4 bottom chord (see Figure 7). This is actually such a common mis-installation that we specifically tested this scenario and have developed an engineering letter on it (note the greatly reduced capacity). In this case the ideal choice would be the H2.5T, which has been specifically designed for a 2×4 truss bottom chord.

H2.5A Installed on 2x4 Truss Bottom Chord — Figure 7. H2.5A Installed on 2×4 Truss Bottom Chord

H2.5T Installed on 2x4 Truss Bottom Chord — Figure 8. H2.5T Installed on 2×4 Truss Bottom Chord

Fasteners with Hurricane Ties

It’s also essential to pay close attention to the diameter and length of the fasteners specified in the Simpson Strong-Tie literature. While many hurricane ties have been evaluated with 8d x 1½” nails for compatibility with nominal 2x roof framing, some require the use of a longer, 8d common (2½” long) nail and others require a larger-diameter 10d nail.

When specifying products for a continuous load path, it’s a good idea to select connectors that all use the same size nail to avoid improper installations on the job. It’s much easier if the installer doesn’t need to worry about which size nail he currently has loaded in his pneumatic nailer.

Wall Framing

Do your roof and wall framing members line up? If so, creating a continuous load path can be made simpler by using a single hurricane tie to fasten the roof framing to studs. The H2A, H7Z, and H10S are some of the connectors designed to do just that. If your framing doesn’t align, though, you can use two connectors to complete the load path. For simplification and to reduce potential mix-ups in the field, consider selecting the same hurricane tie for your roof framing-to-top-plate and top plate-to-stud connections, like the H2.5A.

Figure 9. Roof-Framing-to-Stud Connection with Single Hurricane Tie

Besides the added benefit of fewer connectors to install, using a single hurricane tie from your roof framing to your wall studs can eliminate top-plate roll, a topic discussed at length in one of our technical bulletins.

Other Factors When Selecting Hurricane Ties

Some additional factors that may influence your selection of a hurricane tie are:

Environmental factors and corrosion should be considered when selecting any product. Nearly every hurricane tie is available in ZMAX®, our heavier zinc galvanized coating, and several are available in Type 316 stainless steel. A full list of products available in ZMAX or stainless steel may be found on our website. On a related note, be sure to use a fastener with a finish similar to that of the hurricane tie in order to avoid galvanic corrosion caused by contact between dissimilar metals.
When retrofitting an existing structure, local jurisdiction requirements will also influence your decision on which hurricane tie to use. As an example, the state of Florida has very specific requirements for roof retrofitting, which we outline in a technical bulletin, and they specifically mention the roof-to-wall connection. Be sure to check with your local city, county or state for specific requirements before you decide to retrofit.
Availability of wind insurance discounts in your area could also affect your decision on which type of hurricane tie to use on your home. Your insurance company may provide a greater discount on your annual premium for ties that wrap over the top of your roof framing and are installed with a certain minimum quantity of nails. Check with your insurance provider for additional information and requirements.

Although this is a lot to take in, hopefully it makes choosing the right hurricane tie easier for you on your next project. Are there any other items you consider in your design that weren’t mentioned above? Let us know in the comments below.

DoD-Compliant CFS Wall Framing Design

Back in the year 2000, the U.S. Department of Defense (DoD) was charged with incorporating antiterrorism protective features into the planning, design and execution of its facilities. The main document developed to meet this requirement is the Unified Facilities Criteria “DoD Minimum Antiterrorism Standards for Buildings” (UFC 4-010-01). The current version was published in October 2013. This document covers what is most commonly referred to as “blast” design.Continue Reading

Construction Referees: Evaluation Processes for Alternative Building Products

construction-referee There are products used in every building not referenced by the codes or standards.
These products can impact safety, public health and general welfare through their effect on structural strength, stability, fire resistance and other building performance attributes. I-code Section 104.11 (Alternative materials, design, and methods of construction and equipment) provides guidance on how these products are approved for use in the built environment and identifies the Building Official as the decision-maker. This is similar to a referee determining a player’s compliance with the rules.

Building Officials see submittals for a wide variety of alternative building products ranging from the simple to the very complex. The amount of data included in these submittals and their relevance and completeness varies significantly from insufficient and minimal to complete and very thorough. In the absence of publicly developed and majority-approved provisions, the Building Official is tasked to ensure the data provided is appropriate and adequately proves the alternative product meets code intent to protect public safety, no matter the product type or complexity. This is compared to the robust code and standards process in which committees with balanced representation publicly develop and deliberate on provisions in order to protect public safety. The question arises whether the 104.11 requirement implies that a similar robust process be used in the development of test and evaluation requirements for alternative products as is used for the development of code and standard provisions where there is public debate, resolution of negative opinions and a majority approval of the requirements. Requiring a similar code development process for alternative products would seems to make sense. Otherwise, a less rigorous process might be employed by those seeking to avoid a more robust code and standard process so as to achieve quicker and less stringent approval for their alternative products.

Some may argue that having to use a “code-like” evaluation process for alternative products would add too much of a burden in time and cost, and that it’s not necessary since individual registered design professionals and building officials have enough time, resources and expertise to determine acceptability. But this begs the question of why a similar public majority-approval process should not be required for new products as it is required for code-referenced products. Another question that comes up is ongoing acceptance of an alternative product, as their manufacture may have changed since their approval. Additionally, different jurisdictions have different expertise and resources and this can lead to different standards for approval for alternative products, leading to inconsistency.

Is there a solution which balances providing innovative and cost-effective alternative building product solutions to the industry in a timely manner with providing a thorough product assessment using a process similar to the codes and standards to better ensure consistency and public safety? Accredited building product certification companies, or evaluation service companies, that use a publicly developed and majority-approved acceptance or evaluation criteria and publish an evaluation report with the product’s description, design and installation requirements and limitations provide such a solution. These evaluation service companies are a third-party resource for building officials to assist in their determination of whether an alternative product meets code intent and should be approved for use in their jurisdiction.

The number of evaluation service companies has been increasing. The ICC Evaluation Service and the IAPMO Uniform Evaluation Service, two of the better-known such companies, are both ANSI accredited to ISO/IEC 17065 (Conformity Assessment – Requirements for bodies certifying products, processes, and services) to provide building-code product certifications (ICC-ES, IAPMO UES). However, accreditation by itself mainly verifies a certain process is implemented to ensure consistency and confidentiality. Both companies also have a public acceptance or evaluation criteria process. This process includes an evaluation committee made up of building enforcement officials. These officials evaluate the proposed criteria, listen to expert and industry input and only approve the criteria by a majority vote if products evaluated to those criteria will meet code intent. This is similar to how the codes and standards are developed — a transparent public process and a majority approval of requirements and not just an opinion of one or a couple of individuals.

The alternative building product review process for ICC-ES and IAPMO UES is similar and has the following important components.

CRITERIA: The accredited product evaluation service develops an acceptance or evaluation criteria, with the manufacturer’s and public’s input, that is publicly debated, revised and ultimately approved by a majority vote of a committee of building enforcement officials.
TESTING: The manufacturer contracts out to an accredited independent third-party test laboratory to either perform or witness the product testing in accordance with the criteria.
REVIEW: Registered design professionals with the accredited product evaluation service evaluate the testing and analyses performed and sealed by registered design professionals with the manufacturers or their representatives. The product evaluation service then publishes the evaluation report to their website, and the report typically contains the product description, design and installation requirements andlimitations.
CONTINUOUS COMPLIANCE: The manufacturer’s quality system is inspected at least annually by the product evaluation service or an accredited third-party
inspection agency to ensure that the product currently being manufactured is the same as that which was evaluated.

While the term “product evaluation” is sometimes used, it is often “product certification” or “product conformity assessment.” ISO/IEC Guide 2:2004 defines “conformity assessment” as “Any activity concerned with determining directly or indirectly that relevant requirements are fulfilled. Some “product certification” companies also provide “product listing” services for when testing and evaluation requirements for the product are already in code-referenced consensus standards, making the development of acceptance criteria unnecessary, thus simplifying the process.

A couple of previous blog posts on evaluation or code reports that you may find informative discuss steps to obtain an evaluation or code report and provide a checklist to determine adequacy of a report.

A mechanism is available to the building industry to provide innovative and cost-effective alternative building products in a timely manner that implements a public and majority product acceptance criteria process, similar to the codes and standards development process. This solution involves the Building Official referencing building product evaluation service reports, based on acceptance criteria, offering a robust evaluation better ensuring that an alternative product meets code intent, thus protecting the public. In fact, several jurisdictions do require evaluation service reports for alternative products.

Should there be an easier path to approval for alternative products than for code-referenced products? What is a reasonable path to product approval? What basis do you use in reviewing evaluation or code reports to determine whether an alternative product is “in or out of -bounds”? We’d love to hear your thoughts.

Five Simpson Strong-Tie employees had the opportunity to participate in a week-long Habitat for Humanity build in the small town of Amarante, Portugal, in late April. The company decided to allocate the funds for the CWP to Habitat’s Global Village program, allowing these employees to help renovate and remodel the older home of a widowed mother (Doña Margarida Ribiero) and daughter (Sonia) living in the Portuguese countryside.

Building with Habitat for Humanity in Portugal

Five Simpson Strong-Tie employees had the opportunity to participate in a week-long Habitat for Humanity build in the small town of Amarante, Portugal, in late April. The group was originally scheduled to work on a Habitat project in Nepal late last year as part of Habitat’s Jimmy and Rosalynn Carter Work Project (CWP), but following the signing of a new constitution and civil unrest in the country, the project was canceled.Continue Reading