Micro Lam Specifications

[bozobozo]

My application for a building permit is held up right now. The approving official wants "specs on micro lams from manufacturer (not generalized) for this job". I'm a little confused. I just got the notice in the mail and have not been able to talk to him yet.

Each microlam in the plans is specifically called out, eg. over the 9ft garage door we are calling for a "triple 1 3/4" x 117/8" 1.9E Microlam". Each was either specified by or load checked by a structural engineer. As long as we use the specific type of microlam called out, shouldn't the manufacturer be irrelevant?

 

[mark handler]

Each manufacturers Microllam have different properties. Specified Strengths and Moduli of Elasticity vary. Boise Cascade, Georgia-Pacific and Trus Joist are some of the manufacturers. Find the one that meets your structural engineers design and provide the cut sheets for that Microllam

 

[Mark K]

The material is LVL lumber and is recognized by the code in IBC Section 2303.1.9 as structurally composit lumber.

To ask for a specific manufacturers data at time of plan check would be equivalent to requiring you to specify a particular manufacturer of glu-lam at time of permitting. If this is the case I would suggest that the building official is over stepping.

The engineer should specify that the product complies with the provisions of IBC Section 2303.1.8. Reference compliance with ASTM D 5456 and clearly specify all of the options listed in the standare. This should be all that the plan checker needs during the plan check.

During construction evidence should be provided that the product installed complies with the product specified. Normal pratice is that this information is reviewed by the design professional but is not submitted to the building official.

There are several options for the building official that wishes to close the loop. The easiest would be for the building department inspector to look at the stamp on the installed LVL members and verify strength and other properties listed on the stamp. Under IBC Section 1703.4 the building official can require an engineering report showing compliance with ASTM D 5456 but there is no reason why this information cannot be provided during construction. If the building official is halfway reasonable this should not be an unreasonable burden. Unless there are problems or specific reason to suspect that the delivered members are not compliant te building official should have noreason to require more.

 

[Sifu]

You don't say if the plans are sealed. I see a lot of people that specify an LVL that are not engineers, though they are often thought to be. If your plans are sealed and you follow the direction of the plans I would accept them unless I had a reasonable suspicion that something wasn't right. I guess the level of detail provided would make a big difference. If the plans are not sealed then I would definately require beam calculations and specs for each beam, specific to the job and particular location.

 

[Mark K]

The appropriate level of calculations should not be determined by whether or not a design professional seals the drawings. The design professional's seal does not excuse the building official from his obligation to review the submittal documents.

In most states the preparation of the calculations would constitute the practice of engineering or architecture and would require that the documents be sealed and signed by a registered design professional. Thus unless there was a specific exemption in the licensing laws calculations could not be prepared by a non-licensed individual.

 

[Sifu]

Not saying an engineered design constitutes an excusal to review. I'm saying if the plans are not sealed then the calculations need to be performed. Whether a particular jurisdiction or state law requires an individual LVL to be designed and sealed is another matter. In the original post it sounds like the plans showed up with LVL's drawn on the plan but no seal and maybe a spec book. I get this from time to time too. It is possible a DP "called them out" and "load checked" them but without a seal who knows? It sounds like the reviewer is looking for a beam calc from the manufacturer/designer that is specific to the job and location, that can be checked for accuracy. Since we still don't know the detail level of the plans submitted its all just speculation at this point.

 

[bozobozo]

Before we submitted the plans for review we asked if the plans needed to be sealed. We we told "no...unless we were planning something unusual or outside of code". Official used an example of a "concrete ceiling" as something unusual.

I had a licensed structural engineer review the plans prior to submission and he performed all the header calculations and submitted those calculations (using StruCalc) in a "sealed" package.

 

[mark handler]

The StruCalc calculations will identify the manufacturer of the Micros

Look up that manufacturer on the web and provide the ICC or NER report to the planchecker

http://www.icc-es.org/reports/index.cfm?csi_num=06 17 13 &view_details

Also put the manufacturer and size on the plans

 

[Mark K]

Mark H

If the calculations were based on a particular manufacturer the manufacturer should be shown on the contract documents but the impression given by the original posting was that they wanted to specify the product generically. If the product is being specified generically, and there is no reason why this is not allowed by the code, it will not be possible to provide the data prior to bidding.

The code does not require an ICC report (NER reports are no longer being issued). What the code requires is an engineering report showing how the design values are determined based on ASTM D 5456. The ICC report summarizes the results from such an engineering report but is not the report and is not sealed and signed as such reports should be. I realize ICC reports are commonly accepted but formally this is not what the code requires.

You may find that the manufacturer may have a report issued by the APA which is similar to the ICC report. If the building official will accept an ICC report there is no reason why they should not accept an APA report.

Sifu

Unless there is an exemption in state law allowing a non-licensed individual to perform engineering calculations you cannot have calculations that are not sealed and signed.

 

[Mark K]

Requiring that the design be based on a particular manufacture of the LVL could be in conflict with public contracting codes that generally require that multiple manufacturers be able to bid on the project. If this was a public project would the building official be able to override the state contracting laws and require that the LVL's be sole sourced?

 

[mark handler]

Mark HIf the calculations were based on a particular manufacturer the manufacturer should be shown on the contract documents but the impression given by the original posting was that they wanted to specify the product generically. If the product is being specified generically, and there is no reason why this is not allowed by the code, it will not be possible to provide the data prior to bidding.

The code does not require an ICC report (NER reports are no longer being issued). What the code requires is an engineering report showing how the design values are determined based on ASTM D 5456. The ICC report summarizes the results from such an engineering report but is not the report and is not sealed and signed as such reports should be. I realize ICC reports are commonly accepted but formally this is not what the code requires.

You may find that the manufacturer may have a report issued by the APA which is similar to the ICC report. If the building official will accept an ICC report there is no reason why they should not accept an APA report..

Mark

Stop twisting what is said (posted)

read the original post and reread what I posted

And on a side note Not everyone is on the same code as you are, Some NER reports are still vailid, some were renewed as late as 2008, with a three year renewal cycle, contact the ICC-ES Evaluation Service before you make pronouncements.

 

[brudgers]

The material is LVL lumber and is recognized by the code in IBC Section 2303.1.9 as structurally composit lumber.

By that logic, SPF No. 3 are the same SP SS.

 

[brudgers]

Requiring that the design be based on a particular manufacture of the LVL could be in conflict with public contracting codes that generally require that multiple manufacturers be able to bid on the project. If this was a public project would the building official be able to override the state contracting laws and require that the LVL's be sole sourced?

If this was a public bid project, acceptable products would be listed in the project manual. As would substitution procedures.

If you'd seen such a project, I would think you would be aware of that.

 

[GBrackins]

LVL's can be tricky, sometimes. Microlam is the name of proprietary product produced by ILevel/Weyerhaeuser. The use of microlam is similar to someone referring to his circular saw as a Skil saw. Each mill has their own specifications for their LVL's. The closest generic standard I know of is the APA's Engineered Wood Systems LVL stress classification. Of course using this standard as generic specifications eliminates all mills that are not members of the APA because their products do not contain the APA stamp on them.

I specify LVL's in my drawings using the APA EWS LVL stress classifications, or approved equal. We further specify that once the project is awarded to a builder he must have his vendor (lumber yard) provide the building department and us with calculations by a professional engineer certifying their products's compliance with the building code based upon the manufacturer's specifications, and the location and use of each LVL.

This allows the plans examiner to proceed with the knowledge the building department will receive the certified calculations, but only after it has been determined which LVL manufacturer will be providing the LVL's.

I've had issues with building departments wanting to hold up permitting because they did not have a stamp for the calculations. I asked would they hold up permitting if it was a truss floor system? They say, "no, because we'll get stamped drawings from the manufacturer." I tell them the LVL is an engineered piece of wood just like a truss is an engineered piece of wood. I explain their is not blanket "stamp" that covers all LVL's and as soon as we know which product the lumber yard will be providing they will get the stamped calcs before the product is installed. So far no issues.

 

[Sifu]

Mark HSifu

Unless there is an exemption in state law allowing a non-licensed individual to perform engineering calculations you cannot have calculations that are not sealed and signed.

This brings up a point on which I have long been unclear. Does a beam calc for a given LVL need to be a sealed document? The beam calc's I received as a builder from the manufacturer and the ones I accept as an inspector have a given set of criteria. That criteria can be verified. The programs used to design the LVL use a defined set of criteria, stated to be in compliance with the given code. If the criteria used to design the LVL meet the correct code and the input data used to determine what the loads imposed will be are verified, is the LVL not "designed in accordance with accepted engineering practice"? I know this may not count for much but under general conditions none of the jurisdictions I worked in as a builder or an inspector required them to be sealed as a general rule, though I am sure some do somewhere. And FWIW where I am now, as far as I know, I am the first and only person to even require a beam calc, much less verify the conditions under which it is installed. I know that even if many are doing it wrong it doesn't make it right but I would be interested to know how many are doing wrong if my way is wrong.

Is it like a RESCHECK report? That is a report based on trade-off calculations performed by a program. That report should be verified to ensure the input data is what is actually in use and if it is, is not the RESCHECK report accepted without further design oversight?

 

[Sifu]

I had a licensed structural engineer review the plans prior to submission and he performed all the header calculations and submitted those calculations (using StruCalc) in a "sealed" package.

Now I am confused. You seem to have provided a sealed design for the LVL's, which would be specific for the job and locations. I don't know what else the reviewer would be looking for. I must be missing something here.

 

[Mark K]

The original posting suggested a desire to specify the product generically thus at the time of permitting the manufacturer cannot be defined. The ICC or NER reports are issued for a particular manufacture.

My research suggests that the building code in PA is based on the 2009 IBC thus it is unclear how an NER issued in 2008 would be referencing the 2009 IBC.

 

[Mark K]

Sifu

The need for sealed calculations is defined by state licensing laws. Unless the calculations provided by the manufacturer are sealed they would not be acceptable is state licensing laws require sealed calculations.

There is no legal basis for accepting calculations based solely on the fact that they were generated by a specific computer program. It is well understood that any decent sized program will have errors it in. If the program does not comply with the addopted regulations the computer output is wrong. It is the responsibility of the one submitting the RESCHECK report to verify that the results are correct.

 

[mark handler]

The need for sealed calculations was not in the OP. The idea of "sealing" was added by others. The OP stated that his engineer used "StruCalc". The StruCalc program identifies the "manufacture" of the fabricated members. The Spans, Strengths and Moduli of Elasticity vary with the "manufacture". the way I see it the planchecker is just requesting the "manufacture" of the fabricated members, be placed on the drawing. If a different product is to be used, It needs to be verified that it conforms to the required Spans, Strengths and Moduli of Elasticity

This is not brain surgery

 

[jar546]

In PA, the plan reviewer can ask for just about anything he/she wants.

We also ask for the manufacturer specific calculations since the span ability varies by mfg and model #.

This is real simple, just provide it and make sure you use the brand that you spec'd out. We have had that problem before.

 

[KZQuixote]

In PA, the plan reviewer can ask for just about anything he/she wants.We also ask for the manufacturer specific calculations since the span ability varies by mfg and model #.

This is real simple, just provide it and make sure you use the brand that you spec'd out. We have had that problem before.

Come on Jeff. Pennsylvania is a special case, being underlain with so many coal mines the gravitational coefficient is reduced by at least a third.

Bill

 

[bozobozo]

That is what I plan to do - provide the requested info.

 

[DRP]

If the LVL was specified using a manufacturer's software then it will specify which of their products the calculations apply to. Specify that product on the plan, use that product in the field. If the inspector desires a sealed set of calcs notify the supplier and you'll have a set back from the manufacturer in a few days.

You can substitute with a product that has the same or higher allowable stresses.

I use that type software to check humans all the time. It is well understood that engineers are human and on repetitive boring tasks humans tend to lose focus. Those programs are less buggy than several engineers I've met. They get updated to current code, that is flat out rare in human engineers. That door swings both ways

Decide just how many enforcement hats you want to wear, "according to accepted engineering practices" holds the house up, a seal is a chain of responsibility. I don't typically call an engineer for a built up sawn girder, the builder is responsible. My old code book has design values for many species and grades and simply asks that the user size members according to accepted engineering practice. The intent is to get a properly sized member. The question becomes not how to do it properly, that computer can size a beam as well as any human if the input is correct, we need to decide how many incidental side actors a person needs to hire to achieve the goal.

The math being protected here is 7th grade stuff. I'm sure we can legislate that calculating change can only be done in the presence of a CPA, cash registers are notoriously flippant and subject to input error.

 

[DennisK]

Bozobozo, the reviewer may be a bit of an *** but you don’t seem to know your drawings. As pointed out by Gbrackens, you specified a particular manufacturer when you called the LVL’s MicroLams and you specified a particular grade of ML when you called them 1.9E.

It sounds like the reviewer just wanted the design values on the drawing. Granted he could easily look those up but he has a right to expect to see them somewhere.

Print ESR-1387, highlight the right row in Table 5 and give it to the building department. Offer to write the values on the drawing in ink. If your framer buys a different product you will have to submit a change to the building department.

Tried to upload a pdf of the ESR but the size exceeds the limits of this forum. The following link is for the TJ/W specifiers guide that covers the product.

http://www.ce.udel.edu/courses/CIEG407/Class_17/microllam%20design%20properties%20and%20load%20tables.pdf

This is the link to the ESR

http://www.icc-es.org/reports/pdf_files/ICC-ES/ESR-1387.pdf

Dennis

DKEngineering PLLC

dkengineer.com