# UL Classified Block



## ron (May 21, 2010)

When penetrations occur in masonry walls and UL asemblies are used, UL classified block are required. Who should verify these block are being used? The Masonry Special Inspector ? By the time I arrive to perform roughin inspection the walls are already up. I find most inspectors aren't aware of this.


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## Examiner (May 21, 2010)

Have you checked with your local CMU supplier? You may find that most 8" CMU and up have an equivalence rating per Chapter 7 of 1-hour.  If the common CMU used on the project already achieves the rating required why pay extra for the UL number?  Most Architects do not take the time to research this and just spec a UL block.  You local CMU supplier can tell you what the fire rating is for common CMU and what is available for UL CMU.


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## Mark K (May 21, 2010)

I doubt that you will find that there is a "UL classified block"  What I believe is that you will find that the assembly requires block of a certain thickness and having a certain weight (lightweight , normal) and possibly a "Type" classification that is defined in a ASTM standard.  Read the description of the assembly.

The above listed characteristics should be listed in the permit documents and the masonry special inspector should verify compliance with the permit documents.  If special inspection is not called for there is no formal requirement although I would expect that if we are talking about a significant building that special inspection would be required.


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## brudgers (May 21, 2010)

Mark K said:
			
		

> I doubt that you will find that there is a "UL classified block"  What I believe is that you will find that the assembly requires block of a certain thickness and having a certain weight (lightweight , normal) and possibly a "Type" classification that is defined in a ASTM standard.  Read the description of the assembly.The above listed characteristics should be listed in the permit documents and the masonry special inspector should verify compliance with the permit documents.  If special inspection is not called for there is no formal requirement although I would expect that if we are talking about a significant building that special inspection would be required.


UL listed block is available and used in UL assemblies.

http://www.westbrookblock.com/products/blocks/ul/index.htm

http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=BXUV.U910&ccnshorttitle=Fire+Resistance+Ratings+-+ANSI/UL+263&objid=1074331264&cfgid=1073741824&version=versionless&parent_id=1073984818&sequence=1

IMO it should be part of the special inspection if deemed necessary by the building official.


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## Mark K (May 21, 2010)

I am checking with masonry industry sources but I believe that I am still right.

What I believe that we will find is that when a manufacture of masonry units funds the fire test he will have the rating defined as applying only to masonry units manufactured by his firm.  These units are likely no different from any other generic masonry unit but as long as the fire test listed his product by name, as opposed to genericaly, you have to use his masonry units.  This is one of the common games played with fire rating assemblies

In support of my position Section 721.3 of the 2009 IBC specifies some fire ratings for masonry construction and defines the block in terms of type of aggregate, thicknesses, and other technical criteria.  When the fire rating was established using these provisions no UL listing is needed for the masonry units.


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## ron (May 21, 2010)

Mark

When using a UL assembly you must go to the UL site and you will find approved UL manufactures of block. The IBC gives ratings for masonry however only UL classified block can be used in the assembly. I have spoke with UL and IBC. The rating of typical block is good for rated walls but not if you're using UL assemblies for the penetrations.


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## Mark K (May 21, 2010)

I checked with Concrete Masonry Association of California and Nevada and they confirmed my understanding.  UL classified block does not exist, with the possible exemption of the manufacture you noted.    If anybody believes they have to require UL Classified block I suggest that they 1) check with the building official and 2) if they still believe that UL classified block is needed that they check with NCMA.

According to what is being said by Ron the vast majority of projects are in violation of the building code where a fire rating is needed and their are penetrations.  If you believe that UL classified block is required at all penetrations I suggest that you buy stock in the company listed.  It is not standard practice to use different type of block only at penetrations.  This could also cause problems if somebody desires to install a penetration into an existing block wall that had been painted since you would have no proof whether the block had a UL stamp.

Part of the problem when using UL assemblies is that you need to comply with all aspects of the assembly.  This does not always lead to technicaly sound conclusions.  Thus if a different type of mortar is used then the rating does not apply.  None of the assemblies listed addressed penetrtions.  The ones that I checked required running bond construction.

In order to put the UL stamp on the block the manufacturer has to pay UL money thus it is in UL's interest to state what they supposidly said and if they were careful in what they said they may even be correct. Did they state the full truth.  It would be interesting to find out exactly what the person from IBC said.

On a related note what you need is a fire assembly tested per a given standard.  There are other firms besides UL that do this testing.  While the IBC lists several UL standards they also list other generic standards.  TheIBC does not require a UL listing.


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## ron (May 21, 2010)

Mark

You are right you do not have to choose UL assemblies however most Fire Spray and Fire Chaulk  contractors use them. Architects in SC are now requiring a label at each penetration listing the assembly and the person who performed the work. This will be enforced thru out the USA in a matter of time. Any Architect who use the MASTERSPEC will in the future have this in their spec's. It basically requires the same company to perform all assemblies for all subs. Most jobs I am envolved with does this now. I have included a letter written to me from UL for all those that are interested.

Confirming our phone conversation, the various U900 series fire resistance designs published in the UL Fire Resistance Directory all require the use of concrete masonry units (i.e. concrete blocks) bearing the UL Classification Marking.  This fact is conveyed through the asterisk which appears adjacent to the description of the Concrete Blocks in each of the designs.  That asterisk is defined at the bottom of each design as "Bearing the UL Classification Mark".  Beyond that, the blocks must be supplied by the manufacturer shown in the design.  If the design states "See Concrete Blocks category for list of eligible manufacturers.", then it is necessary to review the individual manufacturer's listings within Concrete Block (CAZT) category for those manufacturers eligible to produce block for the design in question.  This is best accomplished through the use of the UL Online Certifications Directory at http://www.ul.com/database.  Enter CAZT into the box adjacent to UL Category Code.  Then Refine Your Search using the specific design as a keyword (e.g. U901).  That will then give you a list of the manufacturers who can supply block for that design.

Please let me know if you need anything further.


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## peach (May 22, 2010)

CMU is exactly what it is.. CMU.. there's not much you can do to it to increase its "fire resistance"..   add perlite insulation maybe..

IF one manufacturer is UL rated, and that's the product specified.. you'll be watching them unload their delivery.

I wouldn't worry about it from a code perspective.. it's a QA issue for the owner to deal with.


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## brudgers (May 22, 2010)

peach said:
			
		

> CMU is exactly what it is.. CMU.. there's not much you can do to it to increase its "fire resistance"..   add perlite insulation maybe..IF one manufacturer is UL rated, and that's the product specified.. you'll be watching them unload their delivery.
> 
> I wouldn't worry about it from a code perspective.. it's a QA issue for the owner to deal with.


The main places the U.L designs come into play is with 4 hour walls, 4" partitions, and cmu curtain walls.


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## ron (May 23, 2010)

Brudgers

UL designs apply at all rated penetrations reguardless of the hour rating or the material.


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