# R301.1.3 Accepted Engineering Practice



## Francis Vineyard (Dec 22, 2010)

What does this really mean? When does it become accepted pratice?

I’ve failed a commercial job where there was a single layer of very reputable house wrap under stucco; the manufacturer’s engineer approved it! In residential construction Deck ledger attached through brick veneer supporting a beam, engineer approved it. A ledger attached to a brick wall using lead shield lag screws supporting a beam for a second story addition and the other half a flat roof, engineer required two more screws at the beam. 

2” x 4,” 12” oc supporting 2 stories,approved. Engineered floor joist over bored according to their specs, approved. These are just a few that immediately come to mind. 

It gets exasperating sometimes.


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## Uncle Bob (Dec 22, 2010)

Francis,

An Engineer cannot under engineer; or use engineering to undermine the requirements of this code.

R301.1.1. states that "As an alternative to the requirements in Section R301.1 the following standards are permitted *subject to the limitations of this code.*

And, R301.1.3 states "When a building of otherwise conventional constructiion contains structural elements *exceeding the limits of Section R301 *or otherwise not conforming to this code, *these elements* shall be designed in accordance with accepted engineering practice.

In other words; if the structural elements are within the scope of the IRC; then an Engineer cannot lessen those requirements by placing a stamp and signature on a piece of paper; and, cannot "engineer" below the requirements of the IRC.

The minimum requirements are set in the IRC; and no one can lessen those requirements; not even the Building Official who is the only person given the authority to interpret the IRC (R104.1).

Hope this helps,

Uncle Bob


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## mmmarvel (Dec 22, 2010)

While I know what you are saying UB, I'm not sure how that is always implimented; my limited experience is that like all inspections, it's sort of a case by case basis.  Each case is in fact the individual inspection.  When I was lucky (more often than not) I was able to see the do-hicky that the engineer had designed, did some common sense observations, followed my load paths and probably 8 out of 10 times it worked.  About 10% of the time the 'work-around' was harder to spot, figure out, etc., in those cases I figured the engineer stamp was what was taking the liability.  The times that I really loved was when they were specifying a post, a beam, a whatever that wasn't there, it was the place that we were suppose to connect to or hang a connection from.  Sometimes the contractors became very creative with trying to figure out and do the best they could with the engineer's instructions (which I would call the engineer on and we'd have to work something totally different).  The other times, the contractor would tell me that he had talked with the engineer and despite that beam not being there, the engineer insisted he make that connection none the less.  At those times the contractor usually discussed it with me (because he couldn't connect with a beam that didn't exist) and I had to call the engineer and have the argument all over again and I'd tell him that since the field work didn't match his plans I wasn't going to pass it.  About half the time the engineer would finally show up out in the field to actually see what we were talking about.  Always appreciated an engineer who would bother to get off his duff and see whats what in the field.  Finding and pointing out things that won't work (in real life, as we see them) has always seemed to me to be part of my job as an inspector regardless of what the plans are stamped with (how many times have we found an approved set of plans that the examiner had missed something), we're all human - even plans examiners and engineers (shhh, don't tell the engineers that).


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## DRP (Dec 22, 2010)

According to the principles of engineering taught at the state land grant university, which is accepted engineering practice. Notice it does not say "by a licensed engineer" but "according to accepted engineering practice". My interpretation of that intent goes back to the old CABO code, for instance read the footnote under the girder table.

It also says "subject to the limitations of this code". As an example, if a beam meets the acceptable loadings and deflections specified in the code using the accepted, and referenced, methods described in the NDS it doesn't matter what the prescriptive table says, an analysis of a particular situation may give a different result than a generic prescrition. As long as that meets or exceeds the code design criteria it is just as acceptable as the table.


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## Yankee (Dec 22, 2010)

I will have to disagree with UB and DRP. Actual engineering practice (and acceptable at that) may yield a member that falls "outside", even if "lesser" than the prescribed.


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## DRP (Dec 22, 2010)

Can you give an example to clarify?


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## brudgers (Dec 22, 2010)

UB,

"or otherwise not conforming to this code" includes items which are less than specified in the prescriptive tables. Such items may be engineered.

Of course, that doesn't mean that crap doesn't get sealed.


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## Yankee (Dec 23, 2010)

I am not suggesting that it is ok to seal "crap", but from my recollection, engineering often yields a more precise value than the "cookbook" values which are meant to cover the widest range of situations. Engineering for a specific situation can lead to a "lesser" value than the prescriptive, and that must be approved (unless the BO is a licensed engineer or brings in a licensed engineer to refute the application, which I have been known to do).

Just thought of a recent example -- a young contractor came in upset because the engineered drawings he had been given for a deck stairway showed thru-bolting as the method of attachment for a member. A very diligent fellow, apparently actually read the deck guide. In this scenario the connection has been engineered and the thru bolting is acceptable as engineered although it is not permitted under prescriptive code. It is acceptable under performance.


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## TimNY (Dec 23, 2010)

I interpret this to mean designed by a registered design professional.  As in the case where a steel beam may be installed in lieu of a girder.

The commentary (I know, it's not law) clearly states "in accordance with accepted engineering practice by a design professional"

As long as the RDP has done the work, I wouldn't be concerned if they specify a member smaller than prescriptive.  The question is, have they done the work.  I usually see the same engineers' stamps and after a while you know the ones that take pride in their work versus he rubber stampers.

Takes pride in work:  comes out to site and has look of disgust on face when I point out issues

Rubber stamper: Initials for "Drawn By" do not match RDP's initials, plans substandard "tecos as necessary", etc..

One of these individuals will require substantiation when things do not appear correct.


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## pyrguy (Dec 23, 2010)

Yankee said:
			
		

> I am not suggesting that it is ok to seal "crap", ...


I can work with engineering designs. I am not a PE but can speak 'engineer' a little.

It is usually not too big an issue, However I did not accept a letter that the PE actually signed and sealed that stated "based on what I was told by the General Contractor..."


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## brudgers (Dec 23, 2010)

Yankee said:
			
		

> I am not suggesting that it is ok to seal "crap", but from my recollection, engineering often yields a more precise value than the "cookbook" values which are meant to cover the widest range of situations.


Absolutely. My point is that it is not uncommon for something which has not been properly engineered to be sealed. Particularly in regards to SFR's.


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## jar546 (Dec 23, 2010)

I have an example of this from a few years ago.

House plans not submitted by a licensed DP.  Rejected for lack of compliance with 602.10, specifically the garage door portal opening.  They planned on 16" of return wall on each side with 2 9' doors and a 12" wall separating the 2 overhead doors.  The ceiling height in the garage was 10-1/2'.  It was an attached garage that was bumped forward of the front of the home.

Without approval, the framer started the job and I caught him when they were about 80% done framing.  I failed the job for multiple reasons and directed them to hire an engineer to figure out how to fix the garage door opening problem.  The framer had not even run the garage door headers into the corner.  The ratio of the door opening to height exceeded the design criteria of the IBC 2305.4.  Since it needed to be engineered and the IBC applies for this situation, I rejected the rubber stamp from the engineer who simply signed off on it as built without calculations provided.  This turned into a ****ing contest between the engineer and myself who filed a complaint against me for rejecting his seal.  The complaint went nowhere as he was wrong.


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## dhengr (Dec 23, 2010)

Acceptable engineering practice has more to do with rational design and analysis methods, tested over time, and accepted by the engineering community, which would be defended by the majority of the engineering community as a proper approach to that particular problem.

DRP’s statement was “according to accepted engineering practice,” and another way I’ve seen it stated is ‘rational analysis in accordance with well-established principles of mechanics and engineering.’  And technically, “by a licenced engineer” is not part of that verbiage.  In fact, I have had people working for me and doing that kind of work, who were not licenced engineers, as long as I supervised their work and assumed responsibility for it, of course I had a hand in their training, so I trusted their work.  Someone sufficiently trained in the science and art of engineering should be able to apply various acceptable methods to arrive at a solution to the problem, and several different people might arrive at slightly different solutions, to the same problem, each rational, explainable and justifiable.  This exercise really says nothing about what school that person got their education from, a few of my people were actually very capable VoTech grads with some good guidance and experience.  Engineers generally find it easier to sit for testing and get registered if they have attended a properly accredited college, land grant or otherwise.  You guys are sorta doing some elementary engineering by interpreting the code or by looking in the tables, etc. and saying ‘yes that beam should be O.K. or that column meets the code.  This assumes you understand how to properly use those tables and their limitations.  Some of you sorta seem bent on running engineers out of the business.  The place that licensed engineering comes into play is that most states (probably all jurisdictions) have laws which say that the practice of Architecture and Engineering should only be performed by people licenced and proficient in those fields.  To me that means if you are not licenced you should be very careful what engineering you do, you should be very careful that you know how to add up all the loads correctly, understand the load paths, all so as not to negate the usefulness of the tables, then  if you can’t pick it out of the IRC tables, you probably need a licenced engineer.

Std. engineering practice or acceptable engineering practice is a slightly nebulous thing until you do something wrong or do something that fails.  Many people get along for years on luck, lack of ever seeing max. design loads, and the grace of God.  But, when they finally end up in trouble, the Court’s terminology is something like, ‘in a manor which a prudent engineer would perform this function,’ and there will be plenty of experts there to refute that person’s prudence and use of rational methods, and then they use the ugly word negligent, and then you’ve got a real problem on your hands.  The sad thing is that some other people who strut around claiming to know everything, and doing engineering in a dictatorial way, are not held to that same std. in court.

The IRC is a prescriptive code written and engineered in a conservative way with the idea of keeping you and house builders out of trouble in most cases, and with the realization that there probably won’t be much engineering oversight on most of the covered projects.  I can do many things by following the IBC, that your code won’t allow, they take full engineering advantage of the materials, and our design methods, and I wouldn’t expect to get any hassle in getting them accepted by your bldg. dept. or a higher authority if needs be.

Accepted engineering practice has been used to set up the IRC, if you stick to the IRC you should be O.K.  Accepted engineering practice does not mean you can practice, or are really practicing engineering because you can pick a joist or beam out of an IRC table.  If there is a question about accepted engineering practice in your mind, you should certainly not be doing any engineering, and this determination is beyond your purview.  If the engineer’s work fails to meet the code, and you can point to specifics, where he can’t legitimately explain how his approach still complies, you probably have a case.  Otherwise, I would make him provide calcs., sketches, drawings, written explanation of how his method complies, and then let him assume the full responsibility which he does every time he signs construction documents.  You sorta have to be able to explain and defend your objections to his details, methods, etc., unless you can point to a code sentence which says “he can’t do that,” using exactly those words with his picture and his detail as accompanying figures, a & b.  It would seem to me that you generally have some obligation to tell then why you are objecting to the situation.  Surprisingly enough, over 45 yrs. I have had very few objections or red lines from plan checkers, or bldg. inspectors; very few disagreements which I could not explain and resolve to the mutual satisfaction of both of us.  I also knew when to pick my fights, and if a two bit addition would please an ornery inspector, I told the contractor do it, for me, then you can buy me lunch, because if I have to go argue with his boss my time will cost you more than this fix, and he’ll just be the ****yer because he got overruled in front of you.


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## Mark K (Dec 23, 2010)

It is inappropriate for the code to refer to “accepted engineering practice”.  Such a term may be appropriate for discussions regarding legal liability but not code compliance.  Interpret the requirement without the reference to "accepted engineering practice".  If it complies with the provisions in the IRC or IBC then it is accepted.  If it is not, then it is a non-conformance that may at the discretion of the building official be accepted as an alternate means of compliance.

The code provisions dealing with approval of alternate means of compliance require the performance to equal or exceed those defined by the code.

The issue of the engineer taking liability is irrelevant since the responsibility of the building official to accept the alternate cannot be delegated to the Owner or the engineer of record.


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## Yankee (Dec 23, 2010)

Dhengr "like button"


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## Yankee (Dec 23, 2010)

Mark K said:
			
		

> The issue of the engineer taking liability is irrelevant since the responsibility of the building official to accept the alternate cannot be delegated to the Owner or the engineer of record.


Accepting an alternate compliance based on documents submitted by a licensed professional DOES shift the responsibility to the  licensed professional.


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## DRP (Dec 23, 2010)

Yankee, The deck connection met the loading requirement, a properly engineered solution. The applicant simply needs to show that the element was designed in accordance with accepted engineering practice and that the element is compatible with the perfomance of the conventionally framed system. No problem there, the AF&PA's connections calc gives the same output as the NDS tables.

jar, Sounds as though the design was not to accepted design criteria nor to accepted engineering practice.

These examples are reinforcing my point. It doesn't matter who is designing these simple projects, it only matters if they are doing it properly. As far as putting engineers out of business, no, but they should certainly have better things to do than figuring out a garage portal beam or a stair bolt for a SFR.

My example of the week; the engineer had the plans for over a month, several emails with additional sketches explaining load path, 2 phone conversations, two office visits. The steel girder arrives, we talk more... he somehow didn't really think the roof was going to load the beam. So I've checked, done the math myself and have ordered 2 "decorative" 24" deep lvl's that I'll slip in above to take the load around the stamped work. This is not the first time and this type of thing has happened with multiple design pro's, SFR isn't "worth the bother" for them to actually engage their thinking cap. What I am advocating is broader knowledge amongst the trades and enforcement so that we all know what we know, there is no dark art to what we do, everyone is on board. And if someone is capable of simple work on their own, you should be able to spot it, understand it and allow it as has been the intent for some time. People will rise or fall to your expectations. Working around stupid carpenters? look in the mirror.

Another example from this summer. Exposed timber porch beams, sized as much for aesthetics as structure. I used Fb 540, etc, did the math and it checked. BO required engineered design, the engineer used Fb 1150, etc and the WSDD tables, it also checked. The engineer was not wrong, I was being very conservative, any AHJ should have seen it in the math. He didn't. I politely pointed it out, smiled and walked out. The engineers fee was 1/3 of that element's cost. It isn't me putting you out of work. No sir, quite the opposite. And yes Dhengr, I am enjoying your posts.


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## Yikes (Dec 23, 2010)

An example:  years ago I submitted a pre-engineered steel building for plan check.  The plan checker told me the member sizes and connections were undersized when compared to prescriptive code, but instead of saying it was "incorrect", he said "provide calculations to justify..."

The calcs that came back were hundreds of pages thick.  The checker said that the building company had utilized some obscure methodology developed by a Russian engineer in the 1950's to save a few pounds of steel cost... he hadn't seen it since his days in grad school.  It was a "generally accepted" engineering theory by PhDs, but not a "widely utilized" in practice due to its complexity (computing power was still expensive back then).  The plans were accepted, and the building still stands.  The design met or exceeded the performance intent of the code, even as it appeared to be less than the prescriptive method of the code.

The important thing here is that the structural engineer of record was not hiding behind his stamp, and was not afraid of sunshine peer review of his calculations.

Also, "accepted engineering" does not preclude innovation, or prohibit exploration of new ideas.

As an extreme example: for the engineer who wants to propose a system or design that's never been tried before, the "generally accepted" method may be an expensive process of trial-and-error, destructive testing on prototypes under laboratory conditions prior to submitting the design for review by code officials.


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## brudgers (Dec 24, 2010)

DRP said:
			
		

> Yankee, The deck connection met the loading requirement, a properly engineered solution. The applicant simply needs to show that the element was designed in accordance with accepted engineering practice and that the element is compatible with the perfomance of the conventionally framed system. No problem there, the AF&PA's connections calc gives the same output as the NDS tables.jar, Sounds as though the design was not to accepted design criteria nor to accepted engineering practice.
> 
> These examples are reinforcing my point. It doesn't matter who is designing these simple projects, it only matters if they are doing it properly. As far as putting engineers out of business, no, but they should certainly have better things to do than figuring out a garage portal beam or a stair bolt for a SFR.
> 
> ...


Just out of curiosity, you got a license?


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## Mark K (Dec 24, 2010)

Yankee

My point is that the building code and the building official is not concerned about liability and responsibility and liability of others.  The building official is concerned about code enforcement.  Does what is being provided comply with the code.

Responsibility and liability are established by contracts and state and federal laws that the building official does not enforce.

If instead of relying on the proscriptive provisions of the IRC an engineer justifies a design based on the provisions of the IBC he should have no greater liability exposure.  In fact I would expect that in some cases the calculated design may actually reduce his liability given the assumptions made by the IRC may not always be conservative.

If the design professional proposes a solution that does not comply with the provisions of either the IRC or the IBC it must be evaluated in accordance with IRC Section R104.11 or IBC Section 104.11.  When the design complies with the IRC or the IBC the building official is limited to determining whether the design complies with the well defined provisions in the code but when dealing with an alternate means of compliance (R104.11) the building official must make a determination that the proposed design complies with the requirements for an alternate method of compliance.  The building official cannot delegate responsibility for making the determination to the design professional.

When using an alternate method of compliance in accordance with Section R104.11 the design professional will often have a higher liability exposure.  His responsibilities are the same.  Liability is established by the courts not the building official.

When an alternate means of compliance, Section R104.11, is proposed the increase in liability exposure to the design professional is not a result of it being shifted but rather it is because the total liability exposure is greater.  The responsibilities and potential liability exposure of the building official and building department are not reduced by the design professionals choice of IRC compliance, IBC compliance, or compliance with R104.11.  In fact I would suggest that the responsibility of the building official is greater when he has to evaluate an alternate means of compliance.


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## Jobsaver (Dec 24, 2010)

The closest thing I do that might be construed as engineering is when inspecting stick-built house frames. Double pan, tray, cantilevered ceilings, and cut-up roofs, cause frequent concern for wandering off strict prescriptive elements of the code. When is a single LVL adequate to form a ceiling pan? At what point will an additional brace restore a framing element to meet code requirements?

At what length do I allow that "California valley" instead of a true valley rafter. At what span do I allow pressure blocking to attach ceiling joists to a ceiling pan framing member or beam.

We do not see very many engineered plans for SFD's here. Each home is a custom, stick built affair.

I have worked out solutions on particular projects having the help of a competent design professional, but always try to walk away with a new "prescription" easy to convey on the jobsites.

Good accurate conservative rules of thumb are exactly what the worker bee needs. Not, one-time precise engineering using complicated language that will work here, but not in a very similar situation there. This is why I am always pushing for rules of thumb concerning alternatives to the code as written, in particular to the way homes are stick-built here.

"If the lam beam is under 25', and the attic above the garage has limited storage, and there is no roof load on the beam, this size will always work. If loaded with a roof load, always jump up to this size."

"If the pan is formed by a single LVL, you cannot apply a roof brace to that single LVL".

" Since you missed these six anchor bolts, post install two each of this size hardware at each location as remedy".


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## conarb (Dec 24, 2010)

Jobsaver:

In seismic Design Categories D and E it's easy, we just require everything be engineered under the Irregular Structures requirement.



			
				2007 CBC (IBC) said:
			
		

> *2308.12.6 Irregular structures. *Conventional light-frame construction shall not be used in irregular portions of structures in Seismic Design Category D or E. Such irregular portions of structures shall be designed to resist the forces specified in Chapter 16 to the extent such irregular features affect the performance of the conventional framing system.


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