Polyurethane Spray Foam Insulation

I received a good question recently about using Spray Foam Insulation in a building that was planned to be used for refrigerated storage. I have worked on a few of these refrigerated storage buildings this year while I don't recall working on any in the prior five years, so if you hear the building market is cooling down maybe that's what they mean. For Halberg Engineering, it has been another great year.

The refrigerated storage buildings I have worked on in the past have all been constructed of Structural Insulated Panels, or SIP, buildings where the engineered package for the building structure itself has been designed by the SIP manufacturer. This type of project has been very similar to a Steel Building project in which the building and structural engineering for it is provided by the manufacturer of the building while the foundation design and other code design issues must be handled by a competent engineer working on the Owner's behalf.

On the request I received the other day, the builder was inquiring about the use of sprayed foam insulation, a polyurethane product similar to CoreBond, applied to the inside of the exterior steel roofing and siding as a way to insulate the building for refrigerated storage.

Because of the potential fire danger from using foams that may be flammable, there are certain requirements in the code that these insulation producst must satisfy. In my experience, SIP's have their own Wisconsin Building Products Evaluation, such as the panels by Energy Panel Structures, Inc.

SIP's are typically installed without a separate vapor barrier and without a separate thermal barrier required because of the sandwich construction of the panel. Spray on foam products such as CoreBond insulation may require the vapor barrier and a separate thermal barrier to meet the same requirements of the code that the SIP's have.

The best advice I can provide to owners and builders considering the use of these insulated products in their design/build project is to contact a design professional and get manufacturer's data to understand the code implications as early in the design process as possible.

Wisconsin to Adopt IBC 2006

The State of Wisconsin, in addition to being the home of the Green Bay Packers and Halberg Engineering, is also the home of the oldest building code in the Union. The state-specific code changed for the first time in July of 2002 when Wisconsin adopted the 2000 edition of the International Building Code (IBC). The adoption of the 2006 is currently underway and is in the hands of the State Legislature.

I learned today that the anticipated date of enforcement for the new building code in Wisconsin is March 1, 2008.

Building plan submittals that are received at a State Safety & Buildings office before this date will be reviewed under the current code (IBC 2000 with ammendments) and building plan submittals received at a plan review office on or after March 1, 2008 (or the final date of enforcement) will be reviewed to the IBC 2006-based code.

Just one example of changes in the 2006 code, A-2 Assembly occupancies (Restaurants, Taverns, Banquet Halls) currently have a sprinkler requirement for occupant loads of 300 people, but the 2006 IBC code requires sprinkler systems at an occupant load of 100 people or more. Of course the code is a relatively complex set of documents and standards, so I would always encourage owners and general contractors to work with their Design Professional as early in the design process as possible to ensure that any advantage available may be obtained by performing the plan submittal before or after the March 1, 2008 implementation date.

Ring Shank Nails

As I wrote about previously, the release of 2005 NDS Design Aid #4, "Post Frame Rink Shank Nails", allows designers to assign shear values for Ring Shank nails which have not been available since the 1997 NDS. Also referred to as Post and Framing Nails or Pole Barn nails, the shear values are currently a bit conservative, I believe, but current testing being sponsored by the NFBA will provide the technical basis for higher (more accurate) design values for shear AND withdrawal in future editions of the NDS.

One difficulty in discussing nails in general and Ring Shank nails in particular is relating the penny designations common in the construction and building fields to the design standards such as the NDS. My good friend and fellow NFBA T&R Committee Member at Maze nails, Tom Koch, was gracious enough to help me close the loop on this little issue by pointing out to me how the penny designation relates to a specific length in inches and also how the gauge number relates to a decimal inch diameter.

I used his information and Maze's catalog to relate to the NDS for a common side member thickness (1.5") for two common materials used in my projects: Southern Pine (G=0.55) and Spruce Pine Fir (G=0.42). This is the table I generated to show the allowable "unadjusted" shear for these single shear (two-member) connections:


Keep in mind that, for a given diameter, as long as the length of actual penetration, "p", into the main member is at least 10 times the nominal diameter, the shear capacity of the connection does not increase with increased length. The penetration must always be at least 6D and can be adjusted for penetrations between 6D and 10D by taking the design value from the table and multiplying it by the actual penetration p/10D.

For species of woods other than Southern Pine and SPF, different shear values are assigned. The shear values can be adjusted for other considerations in the NDS, such as Duration of load which allows a 15% increase adjustment when the shortest duration of load applied is snow, and a 60% increase adjustment when wind is included in the design requirements.

The best recommendation I have for specifying nails is to use what I call the inch by inch approach: specify the length in inches and the diameter in inches, and then the type of nail (Common, Box, Ring Shank, etc.). For example, 4"x0.177"Ø R.S. Nail is a better description than a 20d R.S. Nail, but both "might" be used refer to the same nail. If penny designation is desired because of common relation in the field, I would suggest using that in addition to (and not instead of) the length and diameter in inch by inch format, such as: 20d 4" x 0.177"Ø R.S. Nail.

I hope this discussion helps you with Nail specifications and reduces errors in the selection and specification of the proper nails for your jobs!

Aaron Halberg, P.E.

Unbelievable!

My wife really dislikes it when I use the word unbelievable... but so many things really seem unbelievable to me. I wonder if you are much different...

Can you believe 2007 is more than half gone?

Can you believe that the days are getting shorter already?

Can you believe that I haven't posted a new update since May 31st?

Can you believe that the Brewers have been in first place a lot longer than that?

It's a wonderful thing... we are surrounded with more information and technology than at any point in the history of the world, and I still find so many things about life, well... unbelievable!

It has been a busy summer, hence the posting rate has dropped off. But I've been trying to "make hay while the sun is shining", as the farmers say. I hope you all take some time during this wonderful summer season to enjoy your friends and family and all the priveleges we enjoy living in the single greatest country on the face of the Earth. God Bless America and those who defend her still today!

Truss Lifting Guidelines

Truss Lifting Guidelines outlined in BCSI offer some very practical and clear guidance for an activity that I hope most builders will be doing a lot of in the busy summer months ahead. These lifting guidelines are summarized in this post, but the BCSI booklet is a very good document to be familiar with for all things related to wood trusses: handling, lifting, installing, bracing, and restraining. I discussed this great document in a previous Structural Integrity post, so let's put our hard helmets on and get into some specifics on truss lifting!

No use of the Single Pick Point?

As shown in the first truss lifting diagram above, the truss lifting guidelines warn that lifting by a single pick point at the peak can cause truss damage. It doesn't guarantee damage if you fail to heed this warning, just as I'll say that a building is not guaranteed to fall down if it is built slightly with a little less strength than I design it for. The BCSI guidelines, as with good structural engineering, make every effort to ensure success with their provisions, rather than threatening failure if the provisions are not followed.

In post frame and other wood construction, the trusses play a significant role in the building's ability to resist the required loads applied through snow, wind, rain, gravity, and earthquakes. Their important role in the completed building and the high capabilities to carry loads has to be measured against the high vulnerability the truss components have to out-of-plane loading and deflection during installation, which is why this topic is so important.

For Trusses less than 30'

The recommended lifting method for small trusses, here defined as trusses less than 30 feet from out-to-out of the bearing point locations, is shown above with two pick points. To avoid the truss being pulled out of plane by its own weight, limitations are put on the amount of compression that is placed on the truss component by limiting the reach of the two pick points to 1/2 of the truss span. Also, keeping the horizontal pull-in force of the lifting reaction low is accomplished by ensuring that the angle between the two straps or chains is 60° or less.

For Slightly Longer Trusses...

For trusses 30' or longer (up to 60' long), a spreader bar is recommended to make sure that there is an overall tension force placed on the truss as it is lifted into place. This tension force is the major force in keeping these larger trusses flat during lifting. The truss' own stiffness to resist bending is not very large, as many of you may have observed during lifting and placement of floor or roof trusses.

Long Span Trusses...For trusses of any length, including those that may be over 60' in length, a spreader bar or stiffback may be lashed to the truss while lifting. This is a good method for a few reasons: 1) The truss lifting forces are transmitted from the lifting cable to multiple locations along the truss length, decreasing the localized stress on each truss to bar connection. 2) The truss reaction from the stiffback is vertical only, which is the trusses strongest direction to resist loads... the horizontal compressive reaction from the lifting straps is absorbed by the stiffback itself. 3) Control of the truss during movement is improved and the hook height can be maintained lower compared to using a spreader bar above the truss.

If you have questions about truss lifting and placement, ask your qualified design professional sooner instead of wishing you had done so later. For a complete discussion of the BCSI provisions, get a copy of the BCSI book for yourself by visiting the WTCA or TPI web page (or following this link: http://www.sbcindustry.com/pubs/BCSIED2-D ).

Minnesota Adoption of 2006 "I"-Codes

Minnesota recently announced the adoption of the 2006 I-Codes (IBC, IRC, etc.) now expected to take effect July 10, 2007. In a memo to all building code officials from Thomas C. Anderson, State Building Official, (available at http://www.doli.state.mn.us/pdf/ccld_code_transition_2007_1.pdf) guidance on transitioning to the new code is outlined. Specifically for projects that were issued permits before July 10th, those who had permits applied for but not received as of July 10th, and for those permit applications received after July 10th.

Additional building code information for the State of Minnesota is available at the Minnesota Department of Labor & Industry web site: http://www.doli.state.mn.us/buildingcodes.html

Post Frame Ring Shank Nails in NDS!

During a revision of ASTM standard F1667 a few years back, ring shank nails were removed from the standard and were subsequently dropped from recent editions of the National Design Specification (NDS) for Wood Construction. Now, thanks to the work of the NFBA T&R Committee under the lead of Patrick M. McGuire, P.E. and with special effort on his part, the ring shank nails are acknowledged by the American Wood Council of the American Forest & Paper Association, keepers of the NDS.

In a just released update to the NDS in the form of NDS Design Aid No. 4, ring shank nails are making their return to the NDS under the new name of "Post Frame Ring Shank Nails". The design aid contains design values for single shear connections to supplement Table 11N (wood to wood) and Table 11P (steel plate to wood). The design aid can be found at http://www.awc.org/pdf/DA4-RingShank.pdf

The NFBA T&R committee has been prioritizing this issue pretty highly in recent years to not only reinstate the nails as part of the standard but also to re-evaluate the design values that were allowed for these nails, believing that specific testing and research will result in more accurate and higher allowable loads for both shear and withdrawal values for use in design.

So, although this release of Design Aid No. 4 is a significant step, the design values it contains are limited to shear values only and these are not significantly higher than a similarly sized common nail. Testing currently being performed for the NFBA should provide the basis for justifying higher allowable shear loads and also the withdrawal values in future editions of the NDS.

BCSI - Guide to Good Truss Practices

The latest Building Components Safety Information (BCSI) book was published in October of 2006 and should be familiar to all contractors, builders, and designers using Metal Plate Connected (MPC) Wood Trusses. At the 2007 National Frame Builders Expo in Indianapolis, I gave a presentation with Brent Leatherman of TimberTech Engineering in which I stressed the importance of this document and the specific recommendations in BCSI-10 which are specific to Post Frame buildings.

The Subtitle is descriptive and accurate: "Guide to Good Practice for Handling, Installing, Restraining & Bracing of Metal Plate Connected Wood Trusses." The BCSI offers many diagrams and photos to illustrate the concepts and guidelines outlined in the text.

The document is available for order ONLINE for $10.20/book or less, depending on quantity ordered and your membership status with the Truss Plate Institute (TPI) or Wood Truss Council Association (WTCA).

This document does not have the force of the building code behind it, but it does create an accepted level of care within the industry which could be used in the event of litigation when bracing, handling, installation or restraint of trusses are involved. Having said that, however, I have heard of some building officials enforcing this guide within their jurisdictions as if they were part of the enforceable code, all the more reason to be familiar with this document!

I have created a new post category ("Wood Trusses") for this entry since I intend to write more about different aspects of this topic, including lifting guidelines, temporary bracing requirements, and permanent bracing practices. If you have any subjects you'd like to see explored here, please let me know!

Construction Hiring Jumps in March 2007

This appears to bode well for the commercial building industry, as reported at SBC Magazine's web site:

Construction hiring jumps; A/E activity suggests more to come; Transportation Costs Down

Nonfarm payroll employment, led by a 56,000-job jump in construction, rose 180,000 in March, seasonally adjusted, the Bureau of Labor Statistics reported today. The construction gain nearly reversed a weather-aggravated drop of 61,000 in February. Since March 2006, total employment climbed 1.4%, compared to 0.3% for construction employment. But nonresidential employment (nonresidential building, specialty trades, and heavy and civil engineering), added 146,000 jobs or 3.4%, more than double the overall nonfarm rate, while residential building and specialty trades shed a combined 129,000 jobs or 3.6%.

Architectural and engineering (A/E) activity, a precursor for nonresidential construction, remains positive. A/E employment rose 57,000 (4.2%) over 12 months, BLS reported. The American Institute of Architects (AIA) reported on March 23 that its index of billings at 300 architectural firms slipped in February but remained above neutral. “Growth in the commercial/industrial and institutional sectors fell slightly this month, but remains elevated overall,” AIA Chief Economist Kermit Baker commented. As for residential billings, “The score indicates that the sector is no longer in freefall, but instead has moderated to a more stable level.” Total revenue of A/E and related services firms rose 1.6% in the fourth quarter, up from a 0.9% gain in the third quarter, the Census Bureau reported in a March 14 release on quarterly revenue for selected services (www.census.gov/qss).

For the rest of the article, please see the SBC web site here.

Complying with the Notice Of Intent (NOI)

The Notice of Intent to disturb ground surface is an obligation for all construction sites of residential and commercial buildings. Starting April 1st, 2007, there are new procedures and filing requirements in place for complying with these obligations on construction projects. I encourage you to read the full explanation of the process and the new changes in a recent post I made on this site called "Soil & Sediment Control and Stormwater Changes".

For projects that will disturb a TOTAL area that is less than 1 acre in size, the control practices are required to be used, including
- Some form of perimeter control (silt fence, as an example)
- Means of keeping soil from leaving site on vehicle tires
- Onsite inlet protection
- Stockpile Protection

For projects that will disturb 1 acre or more throughout the life of the project, there are additional requirements including the filing of a Notice Of Intent (NOI). A plan summary is required to be submitted along with the NOI submittal for all commercial buildings.

At this time, I am recommending all of our builder clients become familiar with this process and involve the Owner's directly in this process on new projects and NOT rely on Halberg Engineering to complete this obligation. The reason is that the Owner / Owner's Agent is going to be required to "monitor and maintain the erosion control measures on the site as per the plan. This includes documenting in a log book, a record of the owner/owner's agent site inspections and maintenance events."

This obligation for site erosion control lies with the Owner and, if delegated to others, needs to be delegated to someone with frequent access to the site and adequate responsibility to control the conditions on the site. The builder seems to be in the obvious situation to best provide this service for the Owner.

Is it something that we could consider just one more legislative hoop to jump through?
Yes.
Is it something that could provide some real benefit to the owner and to our natural resources?
I really believe so.

Most of us might agree that it is difficult to legislate reason and responsibility, but the motives for this legislation appear to be necessary due to many violations of reason in this area in many past projects.

Halberg Engineering can provide assistance in understanding and complying with these requirements. If you have questions after reviewing the information available here, please let us know how we can help!

Soil & Sediment Control and Stormwater Changes

The following letter was received by Aaron Halberg, P.E. on March 30th via e-mail from Randy Baldwin, Director, Integrated Services for the Safety & Buildings Division of the Wisconsin Department of Commerce along with his apology for the late notice due to many last minute decisions:

APRIL 1 SOIL & SEDIMENT CONTROL AND STORMWATER CHANGES

Revisions to the Commerce erosion control and post construction storm water rules become effective on April 1, 2007. The changes to the mandated measures, additional performance requirements and processes are not enough of a change to cause a tremendous shock to Wisconsin’s construction industry, but the heightened awareness and subtle changes may create a tremor.

First of all, what’s changing? Here is a list of what will be different for erosion and sediment control in Wisconsin on April 1, 2007.

* A $25.00 fee must be included with the submittal of an electronic NOI (Notice of Intent) for a commercial building site where one acre or more surface area will be disturbed during construction.

* A $325.00 fee for a paper submittal of an NOI and plan summary. The paper submittal of an NOI and erosion and sediment control plan summary may be necessary when the online NOI process does not match your design methodology..

* NOI submittals to Commerce for commercial buildings will not be accepted without a plan summary. This plan summary will state what methods are included in the erosion and sediment control plan for meetings the performance requirements of Comm 60.

There are three options for this plan summary.
1) The first method is a completed soil loss analysis Excel spreadsheet that creates an answer that complies with the soil loss requirements in Comm 60. This soil loss standard is met by altering the time the site is open or by applying practices to the site.
2) The second method is by complying with the time periods listed in the appendix tables A-60.20-1 and -2.
3) The third method includes the submission of an erosion control plan summary that meets the 80% reduction in sediment contained in runoff from the construction site.

* All buildings constructed in Wisconsin that are under Commerce authority, including one- and two-family dwellings, are required to have an erosion and sediment control plan on site. The plan must meet the requirements of s. Comm 21.125 (3) or s. Comm 60.20(3), Wis. Adm. Code. In most cases, mandated practices create a compliant small site of less than one acre disturbed area.

* All building sites of less than one acre disturbed area must have the mandated practices implemented during the construction period The mandated practices include: some form of perimeter control, a means to keep soil from leaving the site on vehicle tires and through dewatering activities, onsite inlet protection, and stockpile protection.

April 1 Notice of Intent Changes Implementation—FOR COMMERCIAL BUILDING SITES

Information, answers to questions, on line educational opportunities for these subjects, etc. can be found on http://www.commerce.state.wi.us/SB/SB-SoilErosionControlProgram.html

On Friday March 30 at 4:00 PM the current web submittal for Notice of Intents will be shut down for conversion to the new application.

After that time, if you want to file an NOI under the pre-April 1 code you must send in the paper Form Number10376 found on our web site at the link below and have the mailing postmarked March 31, 2007 or earlier. http://www.commerce.state.wi.us/SB/SB-DivForms.html#commercial

On Monday April 2 the new version of the Notice of Intent/Plan Data Summary will be activated for web submittal. Click on Number 3 at the link below. http://commerce.wi.gov/SB/SB-DivPlanRevSchedLaunch.html


NOTICE OF INTENT-SOIL EROSION CONTROL PLAN REVIEW PROCESS

Beginning April 1, 2007

The designer/Submitter of the NOI will evaluate the site conditions, determine solutions and prepare a plan to satisfy erosion-and sediment control code requirements

The designer/submitter of NOI will double check the plan using the approved methods from
the code appendix, or the Revised Universal Soil Loss Equation (RUSLE) spreadsheet found on the Safety & Building website and incorporated in the online submittal, or RUSLE 2 program developed by the USDA or some other method acceptable by the department.

Submit via Mandatory online entry of the plan summary and NOI request except for site specific plans that do not comply with the approved methodologies in the code appendix, or the RUSLE spreadsheet, or RUSLE 2.
If the RUSLE method is chosen the submitter will have to complete the spreadsheet on line. The results will be validated and the submittal will not be allowed to be completed until the summary indicates a complying soil loss per acre.

(If your plan is based on a method other than the approved methodologies in the code appendix, or the RUSLE spreadsheet, or RUSLE 2, plan submittal must be done by paper. This paper submittal requirement is also for designs where the overall soil loss is determined using the RUSLE spread sheet for various parts of a site. The fee is the $25 NOI fee +$200 miscellaneous review fee + $100 submittal fee. Submit to our Madison office only. Plans will be assigned upon receipt to the next available opening).

$25 online payment can be made via credit card, or request by the submitter to be invoiced. For the first few weeks in April the credit card functionality will not be ready. Instead, the Submitter of the NOI will be invoiced for the $25. Payment is expected within 30 days of receiving the invoice.

Submitter agrees to self certify compliance (remember to check the box on the web screen first, then submit).

The plan methodology summary and site information is accepted into our database. The data is auto filled into an electronic calculator that determines whether or not the plan meets the acceptable soil loss per acre standard.

An NOI acknowledgement letter/plan summary approval is emailed to the Submitter of NOI and other entered customers for which email addresses were provided.

The NOI acknowledgement /plan summary approval letter is printed and signed by the OWNER . The owner or owner’s agent attaches a copy of the signed NOI acknowledgement letter to the prepared erosion-sediment control plan and maintains those on the building site.

The owner/owner’s agent implements and maintains the Erosion and Sediment Control plan on the site. The owner/owner’s agent monitors and maintains the erosion control measures on the site as per the plan. This includes documenting in a log book, a record of the owner/owner’s agent site inspections and maintenance events. This log book is kept on the building site and available for inspection.

Inspectors make periodic site visits to monitor erosion-sediment control compliance.

Acknowledged NOI’s will be displayed on the web in the “Search Commerce Records” database by Fall 2007.

At this time, submitters have a choice to submit the NOI’s and plan summary to the Department of Commerce or to Commercial Building Certified Municipalities for projects within their jurisdiction, unless that municipality chooses to waive the submittal to Commerce.
Inspection is the responsibility of the Certified Municipality. The municipality may also require other local reviews and permits.

Commercial Building Delegated Agents are not mentioned in Comm 60 at this time. In the future, Commerce will work with municipalities for the delegation of erosion and sediment control & post construction storm work.

Where plumbing systems are utilized for stormwater management, plumbing plans are required to be submitted to Commerce or to a Plumbing Agent Municipality in accordance with Tables 82.20 -1 & 2. If the plans include subsurface infiltration serving stormwater dispersal, the plans must be submitted to Commerce or, if, within their boundaries, to the City of Eau Claire, Janesville, Madison, Sheboygan.

New Soil Erosion Rules

There are new Soil Erosion & Sediment Control Rules for the State of Wisconsin which go into effect April 1, 2007. To help educate builders and those associated with commercial and residential building projects get up to speed on this topic, the Wisconsin Builders Association and the Wisconsin Chapter of the Associated Builders and Contractors, Inc. are sponsoring training workshops around the state.

For $60 ($30 to members) the 3.5 hour workshop will share information on Erosion Prevention, Sediment Control, De-watering, Inspections, Documentation, Final Stabilization and a Q&A Session. Workshops will be held from 1pm to 4:30pm in the following cities:

Wausau - March 22

Madison - March 27

Rice Lake - April 3

LaCrosse - April 5

Fond du Lac - April 11

Green Bay - April 26

As the promotional brochure and registration form (available online) reads:

"DID YOU KNOW...These rules establish performance standards for practices to address erosion and sediment control on sites where land-disturbing construction activity is to occur, regardless of the size of the site, and these rules update both the WI Uniform Dwelling Code and the WI Commercial Building Code?

AND DID YOU KNOW...These rules further establish monitoring and maintenance provision for erosion and sediment control?

NO?

Then you need to attend this brief afternoon workshop to learn the new requirements."

Additional information from the Safety & Building Division on the topic of Soil Erosion Control is available on their website at http://commerce.wi.gov/SB/SB-SoilErosionControlProgram.html

Horizontal Siding for Post Frame

Horizontal siding is often fastened over vertical studs in conventional wood frame buildings, so horizontal 2x4 or 2x6 girts used instead of studs on post frame buildings presents a bit of a dilemma... or is it an opportunity? Recommendations for new construction include the creation of a drainage plane behind the siding by using a housewrap over the structure and vertical air channels under the siding (picture at left).

To create the vertical air channels, both conventional wood frame and post frame buildings require vertical members behind the siding. This moisture drainage plane assists with more than just exterior moisture as the membrane is designed to allow moisture out of the wall to atmosphere.

Vertical nailing members will be required at a spacing no greater than the maximum fastener spacing required for the siding. For horizontal vinyl siding, installation specifications recommend 16" o/c fastener spacing and for Fiber Cement siding (such as HardiPlank), 24" o/c fastener spacing is recommended. By attaching vertical members to horizontal girt members, Post Frame wall will have less energy loss through conductivity than an equivalently insulated conventional wood frame wall (since, as shown in the picture, vertical studs would be lined up with vertical strips).

Keep in mind that when horizontal lap siding is used instead of light gauge metal wall panels, a separate method for resisting lateral loads will still be required, such as a layer of structural sheathing or adequately designed diagonal bracing. Also, Post Frame vertical strips spanning from girt to girt should be larger than the 1/2" x 2" strips shown above.

If this topic is of interest to you, or if you have comments to share with others, please share your comments using the link below.

AWC online calculators

The American Wood Council has made a couple handy calculators available for free online. The span calculator will tell you what size and species will satisfy a given load and span conditions or you can have it determine the the maximum span a given size, species, and load condition can achieve. Their most recent calculator is a connection load calculator that can specify the allowable capacity for bolts, screws, nails, and lags. This calculator is based on the latest data available in the 2005 edition of the NDS, which is adopted in the 2006 IBC.

Again, these are handy tools which I encourage you to explore and use. If you have questions about the factors that the provided help cannot answer, contact your favorite design professional for assistance!

NFBA Expo summary online

If you missed it, or if you didn't have time to absorb it all while you were there (like me), the NFBA Expo Exhibitor Showcase and Presentation materials are available Online. There was some great material presented at the show. I reviewed some of these in a prior post on my blog and will review some others soon, including my presentation on Truss Bracing according to the BCSI documents.

I encourage you to keep on learning!

Mezzanine and Egress - Code Questions

In a series of discussions on the building code, I'd like to start today with some thoughts on the building code in general and also about accessibility... specifically for Mezzanines and for accessible egress.

It is always interesting when one of my clients calls out of the blue with a question for me. I never know where the discussion will lead. Helping find the answers to these questions is one of my favorite parts of this job. It can be overwhelming at times, but I am thankful that I can help in this area, so please keep them coming and I'll keep on learning right along with you. I believe we need to keep learning every day and take an interest in the well-being of others. Your questions give me the opportunity to do both!

Thoughts on the Building Code
The building code identifies minimum requirements and we're always free to exceed these requirements in terms of safety, accessibility, and Structural Integrity. We often want to know what the Minimum Requirements are since, except for lottery winners, the project owners typically have limited resources at their disposal.

The building code dictates what we must do in certain areas of our construction projects, and we offset these requirements by building smaller or spending more to provide the dictated features, such as firewalls, sprinklers, and accessibility. In certain situations where expectations of the building code requirements are not clear up front, the code requirements may halt the project as financially infeasible.

Despite the "Thou shalt..." tone, the building code does have a benefit for the safety of the public in mind. We actually heard of commercial roof collapses during the recent snow falls in the Wisconsin... mostly flat roofs as far as I've heard (none of your projects, I'm sure). But in 2006 we saw the collapse of an ice arena in Germany claim 11 lives and 67 lives were lost in the collapse of a Polish trade hall, so we do have cause to say that some measure of rational design is required to insure the safety of the public.

Accessible Mezzanines
Are mezzanines required to be accessible to the wheelchair bound? I sure didn't think so earlier today. Small mezzanines have certainly been approved without an elevator or accessible ramps, but the Wisconsin Commercial Building Code requires all elements of a our commercial buildings to be accessible, with some exceptions.

The exception for non-accessible mezzanines is in Comm 62.1104(4)(b), and states that floors above and below accessible levels with an aggregate area of not more than 3,000 sq. ft. do not require an accessible route to them. In other words, if your mezzanine will be over 3,000 sq. ft., reason for concern, but the cause may not be lost.

Since code questions are typically more simple than the answers: There are some provisions in Comm 62.1003(2)(h) and (i) which identify some general exceptions to accessibility requirements which allow Limited access spaces (h) and Equipment Maintenance and Repair areas (i) not to be accessible. These areas are viewed by the code as areas where work could not reasonably be performed by a person in a wheelchair and so it negates the requirement for an accessible route to them.

Accessible Means of Egress
The building code requires at least one accessible entrance to commercial buildings, but two accessible egresses. It means we may have a door from a building that could be used during emergency as an accessible egress (when the building's on fire) with the assistance of others which would not be an accessible entrance during normal operation of the building.

The accessible entrance is viewed as an equal access provision to provide equal access opportunity in public buildings. The accessible egress is a life safety issue that allows for the fact that during an emergency (fire, for example), the entrance used to gain access to the building may be blocked by the situation causing the emergency. It is assumed that egress may be accomplished by people working together in the event of getting a wheelchair down a flight of steps during an emergency as long as provisions are made for the person in a wheelchair to have access to communication for assistance from a relatively safe and secure location.

These concepts are covered in the code by the terms "Areas of Refuge" (IBC 1003.2.13.5) and "Exterior Areas for Assisted Rescue" (IBC 1003.2.13.7). In building projects without complete accessibility going into and out of the building, remember to consider the egress requirements during emergency situations. It is not enough to say that "nobody in a wheelchair works here and wouldn't have a reason to come here". Public buildings must not be designed with an inherently dangerous situation based on the assumptions of what level of physical ability people must possess before they use that building. That is a type of discrimination we cannot tolerate.

Frame Building Expo Summary

I attended the 2007 Frame Building Expo last week in Indianapolis. It is hard to absorb all of the information and networking opportunities available at such an event, but I'd like to share some of my highlights as they affect the projects for my business and my clients in the months and years ahead.

On the first day, Prof. Gary Anderson, P.E., PhD from South Dakota State University presented a thorough discussion of the effect that soil backfill has on the stiffness of our embedded post buildings. Gary presented a lot of technical information on how the soil stiffness can be modeled more precisely. If it helps present a visual picture, I typically model the soil for embedded posts as a whole bunch of springs resisting lateral movement of the post with the stiffness of the springs getting higher the further below grade you go. Gary's presentation was aimed at more accurate predictions of spring stiffness modeling in various soil embedment conditions.

Because this whole analysis can affect the amount of stress in the columns and the location of the maximum stress, the modeling that Gary presented is quite important to the basic question of "What size columns do I need?" and it's one reason I have been reluctant to assist others in developing column sizing charts... there are many variables which can have a large impact on the calculated stresses. This is just one of those variables (diaphragm stiffness is another!)

On Thursday, Prof. David Bohnhoff from the University of Wisconsin gave a presentation on Post Frame Foundation Options. He presented the basic factors of deciding whether or not to embed the posts in the ground, a decision that seems to be trending toward "not to embed" in my opinion. He discussed the options in terms of structural considerations, construction impacts, and other issues to consider.

Dave also presented some great information on Grade Beam Foundations, or Frost-Protected Shallow Foundations (FPSF). These foundations are not designed to extend to frost depth but to be protected from the effects of Frost by other means. You need three things for frost heave 1) Water, 2) Freezing Temperatures, and 3) Soils conducive to ice lense formation. Removing one or more of these factors from the soil beneath the footings reduces the frost heave potential. Dave ended his presentation with a discussion of Thermal Envelope Requirements and, as with all of his presentations, great graphical displays accompanied all of the information. (Dave has a wealth of great Post Frame information on his website.)

Later on Thurday, Charles Carter of the American Institute of Steel Construction (AISC) discussed Steel Panel Braced Frames which will be discussed in a soon to be published design guide (#20) by the AISC. These strong shear wall segments could serve as a custom made alternative to products such as the Simpson Strong Wall system. These could lend themselves to use in Post Frame projects where we have a lot of endwall forces to transfer from roof to foundation with very little endwall to do it in, such as Airplane Hangars or any storage buildings with large endwall openings.

For additional summary information from the Expo, including the many exhibitors with popular and new products, you should check out the Rural Builder Buzz blog by Scott Tappa. He gets around and knows a lot about many issues in the industry that I don't have the time to keep up with.

In future posts at Structural Integrity, I will try to go into more detail about these engineering topics presented here as well as others that I think are relevant. I'll also try to use this forum to answer some of the questions that come up from clients as a way to share information with more people who may have similar questions. I hope you find this useful.

Have a great day!

Stepping out...

There's something to be said for getting away from the daily routine and immersing yourself in something different for a little time of renewal. The 3 day National Frame Building Expo wrapped up in Indianapolis this morning and although I am looking forward to returning home and seeing my family again, I am taking home some new ideas and some new energy for the construction season ahead.

It was great to reconnect with old friends and meet some new friends. Many of my clients were at the Expo with the opportunity to see the same vendor displays and educational seminars, although we all had our own nuggets to take away from the event. Growth opportunities for the needs of each individual abound at these events for those who are willing to find them.

One of the greatest surprises was learning a little about WebLogging from my friend (and fellow Wisconsin Alumnus) Scott Tappa at the Rural Building News booth. Scott's got a great flair for sharing information and I have always enjoyed his ability to educate me on topics from BigTen Athletics to the latest Building Trends. Thanks to Scott's impromptu lesson on Blogging a couple hours ago, here I sit in a hotel lobby in Indianapolis composing my first Blog Post on my brand new Blogspot!

Scott is so good on the computer that I predict he will find this web site before I can even tell him I have it up and running, so "Thanks, Scott!" for sharing the time with me and being a true ambassador for the Post Frame industry. The exchange of knowledge and ideas is the reason we get together at these conventions and Scott embodies that ability better than most people I know.

It's the little serendipities of life that often bring the largest joys and impacts in our lives!

God Bless America