Pre-Engineered Metal Building (PEMB) Specifications 2

[JoelTXCive]

One of our clients wants to do a 125' x 60' PEMB.

They have been storing emergency pumps and misc equipment outdoors and would like a covered area for storage.

This will be a non-air conditioned space. Unless the fire marshal demands it, the client has no plans for running water either. It's literally going to be covered a lay-down yard with a bunch of overhead doors.

Our plan is for me to design the slab, but then outsource the design of the PEMB.

Does anyone know where I can get some basic specifications for a building like this? Maybe an industry group?

We want some sort of specifications to cite in our contract documents other than the standard "contractor to submit signed and sealed building drawings..."

Thank you in advance.

 

[phamENG]

Metal Buildings Manufacturers Association

 

[JedClampett]

There's a lot of choices you can make to make the building more attractive and long lasting. If you don't choose, you'll get a "race to the bottom" and no one has ever seen the bottom.
I'd ask for:
[ul]
[li]Kynar coated panels[/li]
[li]All members coated with an epoxy or acrylic paint.[/li]
[li]Standing Seam Roof[/li]
[li]Gutters and downspouts.[/li]
[li]Possibly gravity or forced air ventilators (if they drive vehicles in the building and leave them running, you could kill someone).[/li]
[/ul]
These don't add a huge cost, but add a lot of value.

 

[GC_Hopi]

Here is one of the biggest PEMB... and steel suppliers for that matter. They have a word doc and a spec guide. Best of luck. Nucor building systems

 

[straub46]

Most PEMB suppliers work with approved "builders" as well. They're usually a GC who orders a certain number of buildings/tons a year from them. They might not sell to a non-approved builder, so you (or the owner) may need to find the right contractor for PEMB erection.

Also make sure you clearly specify code, snow/MEP loadings, wind exposure, etc. They likely won't check into it much beforehand, and it can get expensive to fix if it's not specified correctly the first time.

Go Bucks!

 

[Kuhladula]

If you aren't caring a formal specification sheet, some of the standard quote request documents will ask for the following:
1. Width x Length x Eave Height (X:12 Single/Double Slope)
2. Rigid Frame vs. Post & Beam Endwalls (Hot-rolled vs. CFS)
3. Base Elevations of any columns / stem walls.
4. Colors for wall and roof panel.
5. Standing seam vs. screw down roof (gutters & downs?)
6. Bay spacing as per economic design or set values?
7. Building Code, Exposure Category, Risk Category, Insulation Requirement.
8. Extra loads, like collateral loads or RTUs.
9. X-bracing allowed? Which bays?
10. Opening locations & sizes.

There's a lot of other aspects that could come to play, but that's the basic that you'll want to present to your building supplier. As straub46 stated, most of them act in the same way that Ford/Chevy would act. You're going to deal with their dealer system and not the steel manufacturer itself. The dealer can provide you with any of their specifics. You might want to specify using an AC472-certified supplier if you want a little more confidence to weed out the backyard shops that are all-too-common in Texas.

As phamENG linked above, the MBMA is a great place to start to form a more formal document, but I would turn towards some of the major suppliers to see what they could round up for you. Start contacting them today because a lot of building suppliers are out until next year already...

 

[JoelTXCive]

Thank you everyone. This is exactly what we needed.

The stock MBMA spec's can be a starting point; and then I can investigate the other suggestions you have made.

JedClampett - those are really good points you bring up. Thank you.

 

[Brad805]

Deliveries in our area are terrible of late. I would suggest your client to start considering the various big names. If they can get some budgets you can probably work directly with one to get your client the building that works best. I have been waiting for IFC dwgs for a project around this size for 2months now and I have a GC chomping at the bits to get rolling.

 

[dik]

From my project notes:

MBS LOADING
MBS SHALL BE DESIGNED FOR THE FOLLOWING SUPERIMPOSED LOADS IN ADDITION TO THE LOADS STIPULATED ABOVE:

ALL ROOF PURLINS:
DEAD LOAD = 5 PSF UDL
LIVE LOAD = 5 PSF UDL AND TWO POINT LOADS OF 250 LBS AT ANY LOCATION

BUILDING FRAME:
DEAD LOAD = 1000 LBS VERT DOWNWARDS AT ANY LOCATION
LIVE LOAD = 2000 LBS VERT DOWNWARDS AT ANY LOCATION

HAUNCH:
DEAD LOAD = 500 LBS HOR EITHER DIRECTION AT BOTH HAUNCHES
LIVE LOAD = 1000 LBS HOR EITHER DIRECTION AT BOTH HAUNCHES


METAL BUILDING SYSTEM (MBS)
MANUFACTURER SHALL BE CERTIFIED TO [CSA A660 | CATEGORY MB OF THE AISC QUALITY CERTIFICATION PROGRAM]

THE METAL BUILDING SYSTEM MANUFACTURER SHALL SUBMIT THE CSSBI CERTIFICATE OF DESIGN AND MANUFACTURING CONFORMANCE TO THE [OWNER | CONSULTANT | ENGINEER] PRIOR TO SHIPMENT OF THE PREFABRICATED BUILDING TO SITE

DESIGN STANDARDS FOR THE METAL BUILDING SYSTEM ARE TO MEET THE REQUIREMENTS OF PART 4 OF THE [NBCC | MBC |SBC], CSA STDS S16 AND S136 EXCEPT AS NOTED BELOW

WELDING SHALL BE PERFORMED IN ACCORDANCE WITH CSA W59. MANUFACTURER TO BE APPROVED BY THE CANADIAN WELDING BUREAU, IN ACCORDANCE WITH CSA W47.1 FOR DIVISION 1 OR DIVISION 2

MBS BUILDING TYPE IS [RIGID FRAME CLEAR SPAN | MULTI-SPAN | GABLED | MONO SLOPE]

MIN ROOF PITCH SHALL BE 2:12

MIN ROOF PITCH FOR STANDING SEAM ROOF PITCH SHALL BE 1/2:12 U/N

END WALL FRAMING SHALL BE [EXPANBABLE | NON-EXPANDABLE]

LATERAL BRACING SHALL USE [CROSS-BRACING | MOMENT RESISTING PORTAL FRAMES]

WALL AND ROOF PANELS SHALL BE 26 GA MINIMUM THICKNESS

ROOF PANELS SHALL BE 24 GA MINIMUM THICKNESS FOR STANDING SEAM ROOFS

COLUMN FLANGE BRACING SHALL NOT BE USED UNLESS APPROVED BY THE [OWNER | CONSULTANT | ENGINEER] IN WRITING

ALL STRUCTURAL STEEL COMPONENTS, INCLUDING ANCHOR RODS SHALL BE CERTIFIED AS WELDABLE

PREFABRICATED METAL BUILDING SYSTEM SUPPLIER SHALL SUPPLY ALL ANCHOR RODS, NUTS AND WASHERS TO SECURE THE BUILDING TO THE FOUNDATION. ANCHOR RODS ARE TO BE DESIGNED FOR ALL HOR AND VERT LOADS

REFER TO ANCHOR ROD NOTES FOR ANCHOR ROD REQUIREMENTS

DESIGN OF THE BUILDING FRAME AND ALL COL MEMBERS SHALL ASSUME THAT ALL FRAME AND COL BPS ARE SUPPORTED ON [1" | 1/4"] OF GROUT

SUPPORTING COLUMNS AND BUILDING FRAMES SHALL BE PINNED AT BASE CONNECTIONS

COORD X-BRACING ELEMENTS WITH ARCH TO PREVENT CONFLICT WITH OPENINGS

THE BUILDING MANUFACTURER SHALL PROVIDE A 25 YEAR WARRANTY FOR ROOF AND SIDING FINISH

THE BUILDING MANUFACTURER SHALL PROVIDE A 10 YEAR WARRANTY FOR LEAKAGE

THE BUILDING MANUFACTURER SHALL PROVIDE A 10 YEAR MANUFACTURERS ROOF WARRANTY AND A 15 YEAR SIDING WARRANTY AGAINST DEFECTS IN MATERIALS

THE CONTRACTOR SHALL CARRY A 5 YEAR WARRANTY AGAINST DEFECTS IN WORKMANSHIP

BUILDING LENGTH AND WIDTH SHALL BE MEASURED FROM THE OUTSIDE FACE OF THE GIRT LINE

BUILDING HEIGHT SHALL BE MEASURED FROM FINISHED FLOOR TO THE INTERSECTION OF THE INSIDE SURFACES OF THE ROOF AND WALL COVERING

BUILDING FRAME TOTAL LATERAL DEFLECTION AT THE HAUNCH SHALL NOT EXCEED [H/120 | H/360 | H/600 (PROVIDING CRANE SUPPORT)] WHERE HEIGHT IS THE HEIGHT OF THE WALL

THE TOTAL COMBINED LIVE LOAD DEFLECTION FOR THE GIRTS AND SIDING SHALL NOT EXCEED L/240

THE TOTAL LIVE LOAD DEFLECTION FOR THE ROOF DECK SHALL NOT EXCEED L/240

THE TOTAL LIVE LOAD DEFLECTION FOR THE ROOF PURLINS SHALL NOT EXCEED L/240

THE TOTAL LIVE LOAD ROOF GIRDER DEFLECTION SHALL NOT EXCEED L/180

THE BUILDING SHALL BE COMPLIANT WITH THE REQUIREMENTS OF [ASHRAE 90.1 | THE CURRENT NATIONAL ENERGY CODE]

MATERIALS SELECTED SHALL MINIMISE GALVANIC CORROSION. PROVIDE SUITABLE INSULATING MATL AS NECESSARY

THE MBS SUPPLIER SHALL PROVIDE FOR SUPPORT OF ANCILLARY STRUCTURAL ELEMENTS WHERE NOTED ON THE DWGS. THE METAL BUILDING SUPPLIER SHALL PROVIDE FOR REDUCED DEFLECTION LIMITATIONS AS REQUIRED FOR ATTACHMENT AND SUPPORT OF OTHER BUILDING COMPONENTS

SHOP DRAWINGS SHALL SHOW THE ANCHOR SETTING LOCATIONS FOR THE BUILDING. ANCHOR SETTING DWG SHALL SHOW:
ANCHOR ROD LOCATIONS, TYPE, DIA, PROJECTION AND LENGTH, MAX AND MIN REACTIONS BASED ON THE LOAD COMBINATIONS STIPULATED IN THE BUILDING CODE IN EFFECT IN THE PROVINCE WHERE THE PROJECT IS LOCATED SHALL BE PROVIDED (A TABULAR FORM SHOWING LOADING REACTIONS FOR VARIOUS LOAD CASES IN NOT ACCEPTABLE)

THE BUILDING SHALL BE INSULATED AND THE PREFABRICATED METAL BUILDING SUPPLIER SHALL SUPPLY ALL NECESSARY THERMAL BLOCKS AND INSULATION

INSULATION SHALL BE PROVIDED BY MBS SUPPLIER

PURLIN BRACES ARE TO BE PROVIDED IN ACCORDANCE WITH CSA S136, CLAUSE 8. IN PARTICULAR, FOR A STANDING SEAM ROOF SUPPORTED ON MOVABLE CLIPS, BRACES PROVIDING LATERAL SUPPORT TO BOTH TOP AND BOT PURLIN FLANGE ARE TO BE PROVIDED. THE NUMBER OF ROWS SHALL BE DETERMINED BY ANALYSIS BUT IN NO CASE TO BE LESS THAN 1 FOR SPANS UP TO 23 FT. OR LESS THAN 2 FOR SPANS GREATER THAN 23 FT

FOR COATING SYSTEM, REFER TO COATING SYSTEM NOTES

THE BUILDING SHALL BE COMPLIANT WITH THE REQUIREMENTS OF FM GLOBAL FOR AN [1-60 | 1-90] RATING

Select the applicable parts and edit or add as required.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[SandwichEngine]

I'm a PEMB engineer. You definitely want to call out a manufacturer that's an MBMA member and is IAS certified. AISC used to certify metal building manufacturers but that stopped around 2008 then IAS took over. They audit the crap out of the manufacturer from their engineering procedures to business practices to the fabrication shop. One of the most important things they do is check the welding specs and certify a manufacturer as being an approved fabricator that doesn't require special inspections of CJP welds during fabrication. This is extremely important because a PEMB rigid frame will have CJP welds every time a flange changes sizes. Using someone who isn't IAS certified means that you have no idea of the weld quality of the entire main structure.

Another thing to consider is whether or not the PEMB designers will even look at the structural and other drawings or the specs. About half the companies in the industry simply do not. They make a contract based on a salesman who looks at the drawings but the engineers and detailers never see it. So they drop a column wherever they please don't locate columns directly over your footings, etc. The first set of drawings you see are their construction drawings and the building has already been fabricated. It's up to you to jump through hoops to try to redesign the foundation to get the footings in the right place, etc. I can see how this makes sense for a mom-and-pop shop where the job hasn't gone through a design team but it blows my mind that companies can be profitable with this kind of business model. I don't know how you'd call this out in your specs but just be aware it's a thing. If your building is as simple as it sounds and you're willing to adjust your foundation drawings to their column locations, you'll have more options.

It's also true that most companies use a dealership like process. The problem there is when there's a problem in the field, the manufacturer will argue it hasn't been erected correctly and the builder will argue that it wasn't designs/detailed properly. Their internal squabbles can cost a project time. I'm aware of one company that erects their own buildings. They're located in Athens, TX and they aren't named after the town.

Definitely call out the code, loading deflections, etc.

The basic rule of thumb for PEMB bay spacing is that it's most economical to use 25 ft on center. Obviously this can vary based on the loading conditions but you can't go wrong choosing that spacing.

Your building will also be less expensive if the wall girts are bypass instead of flush because they will lap and create twice the section properties at the laps. This also pushes the columns in to help with the lateral thrust loads that the rigid frames will produce. The building you called out isn't very wide so the vertical loading on the rigid frame won't produce too much lateral kick-out load but it will be more than you've guessed if you've never worked with a PEMB design before.

Lots of building like this get put up with a through-fastened roof. They are going to leak. The roof panel heats up to well above ambient temperature which wallows out the fastener holes and causes leaks. The fasteners have rubber washers but they eventually rot. Maybe your application can afford a few leaks over the years but if not, use a standing seam roof as was suggested above.

 

[dik]

Thanks, I'll update my notes.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

Updated, thanks... also a really good link for metal building systems... Canadian, though, but good info.

https://cssbi.ca/products/steel-building-systems

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[JStephen]

Several years back, I took an "anchorage to concrete" course by this author, with a lot of the emphasis being on these buildings. But I see this book also available:

https://www.amazon.com/Metal-Buildi...1828966/ref=pd_lpo_1?pd_rd_i=0071828966&psc=1

 

[JoelTXCive]

JStephen - I took Newman's class too and was impressed with him and his course material. I think it was in Tampa, Florida 2018 or 2019.

This thread has been greatly beneficial for me, so keep the good tips coming if you have them!

 

[Ron247]

PEMBs have a lingo like no other. You need to get a little familiar with it. Not all PEMBs use the same lingo but here are some common ones.

Width of the building is the span of the steel frames. It is not the smaller dimension of the building.

Length is the dimension that consists of the sum of the bay spacings. It may not be the longer dimension.

Both the length and width do not include the thickness of the wall panels. A 100' wide (frame span) x 60' Long (3 bays at 20') with a 1.5" wall panel is 100'x60' girt line to girt line (or steel line to steel line) and 100'-3" x 60'-3" outside of wall panel to outside of wall panel.

Height is measured at the low eave but can be referred to in several ways. Frame height is top of rafter, actual eave height is top of eave strut, nominal eave height is some distance (generally 1') above the frame height and there is also clear height under the frame. Make sure they know which you are asking for. The nominal eave height is a way of making a 1' allowance for the roof purlin. They may supply a 7", 8" 10" etc. purlin and still be within the "nominal eave height". You will probably wind up with an 8" purlin if you are not in a heavy snow area. As with walls, the height does not tend to include the thickness of the roof panel (generally 1.25" to 2").

AS far as coordinating drawings, I always make my grid callouts and require them to follow mine. They can add more if need, but must use mine for frames spacings, interior columns etc. Do not try to define the corner columns as a "centerline" of column because unless you know the supplier and final column size, you have no way of knowing their location. All other columns can be located by centerline in one direction but not both directions. PEMBs generally define the steel line or girt line as a grid mark.

Some other tips.
-Do not allow fixed based frames. Foundation costs tend to be more and therefore offset any potential steel savings.
-You and Client lay out the bays and interior column spacings. Buildings 70' and less in width do not tend to need interior columns. Greater than 100' tend to need them from a cost standpoint provided they do not mess up your building use. Greater than 150' really need them due to outward thrust at the exterior column bases. If you must have a really wide clearspan that is short, review some alternatives with a taller eave height. Tall buildings tend to have less D+L thrust.
-The option of bypass girts versus flush girts can also be a problem. Flush girts shove the anchor bolts close to the edge of pier stem and they are harder to reinforce for lateral loads. PEMBs never bother to see if their anchor bolt patterns can are reasonable for foundation design. They only cover quantity and pattern, you must devise the foundation.