Do UL listings show MINIMUM sizes, or absolutes?

[Yikes]

A typical UL tested floor assembly (such as UL L593 here) is shown with nominal 2x10 lumber floor joists. My structural engineer wants to use 2x12s, with the occasional 4x12 beam to pick up a point load.

Can I assume that 2x10 was a minimum, and therefore the 2x12 or 4x12s are also compliant with this same assembly?

Is there anything in the UL manual, or in the IBC reference to it, that states that these are minimum sizes rather than absolutes?

 

[cda]

I would say the assembly is not tested with those dimensions.

Look at the specific listing to see if it says anything

 

[Yikes]

I looked at the specific listing (link provided above) and it is silent on minimum vs maximum, etc. At the front of the UL directory, it says that dimensions for walls and partitions are minimum, and spacing is maximum. I don't see it saying anything equivalent for floor or ceiling assemblies.

 

[Keystone]

Contact UL, there technical reps have been a great asset to our questions as situations arose from field conditions.

In one of our experiences sounding very similar to yours the reps had allowed for the increased floor lumber dimension.

 

[cda]

Appears for some assemblies as long as you hit the minimum, and all other listing requirements you can use bigger lumber.

Check the listing you want to use:::

http://lpcorp.com/media/1343/lp-solidstart-fire-rated-assemblies-technical-guide-english.pdf

Plus thought there was a site that you can input some parameters and it would come up with a listing???

 

[Builder Bob]

II. GENERAL

The following information is applicable to all fire-resistive designs described in this Directory. It is recommended that the users review this information in addition to the general guidelines provided for specific materials and construction types.

Authorities Having Jurisdiction should be consulted before construction.



Fire-resistance ratings apply only to assemblies in their entirety. Except for those separately rated structural members supporting tested assemblies, individual components are not assigned a fire-resistance rating and are not intended to be interchanged between assemblies but rather are designated for use in a specific design in order that the ratings of the design may be achieved. Unless otherwise specified in the individual design or certification, attachments to structural steel have not been investigated.



All ratings are based on the assumption that the stability of the structural members supporting the assembly are not impaired by the effects of fire. The extent of damage of the test assembly at the rating time is not a criteria for the rating.

The specifications for materials in an assembly are important details in the development of fire-resistance ratings. Those materials provided with an "*" in the design text are eligible to be produced under the Follow-Up Service Program of UL. Information identifying such materials and the certified companies authorized to provide the materials are located in the product category section of this Directory. The appearance of the UL Certification Mark on the product is the only method provided by UL to identify products that have been produced under its Follow-Up Service.