WA State Warehouse Demising Wall Insulation??

[DTBarch]

Client has an existing warehouse building in the Seattle area, Climate Zone 4. Looking to erect a new steel stud/gyp. board demising wall to create a smaller space for new tenant. No other work occuring in the warehouse or office.

Section C101.4.3 indicates that the provisions of the code apply to new construction without requiring unaltered portions of the building or building system to comply with this code.

Question: In light of C101.4.3, can I assume that we can focus solely on insulating the new demising wall itself?

Table C402.2 of the Washington State Energy Code indicates that for walls above grade with steel framed construction, we need to provide R-13 plus R-10 continuous insulation. Does that requirement apply to our demising wall??

Question: If so, what does that wall detail look like? Is it feasible to sandwich R10 rigid between steel stud and gyp bd to achieve the ci requirement? Exhaustive search for this topic online yields no help. Plenty of ci applications for exterior walls, but don't see anything relative to interior. Am I missing something? Is ci really needed in an interior warehouse demising wall? I'm an absolute newbie on this topic, so any insight would be appreciated.

 

[RLGA]

C402 applies to the "building thermal envelope," as mentioned in C402.1, which is defined as:

The basement walls, exterior walls, floor, roof, and any other building elements that enclose conditioned space or provides a boundary between conditioned space and exempt or unconditioned space.

Therefore, an interior wall is not part of the building thermal envelope, so the requirements of Section C402 are not applicable.

 

[JBI]

While I'm inclined to agree with Ron generally, the OP indicates that this is to create a new tenant space.

Taking that into consideration, what is the likelihood that one tenant could be using their space (and heating/cooling it) while the adjoining tenant is not?

Will there be a separate HVAC system?

Whether or not the Code 'requires' it is one consideration, but not the only one.

 

[steveray]

Also agree with JBI....You have to really look through the IECC and scoping......

101.4.4 Change in occupancy or use. Spaces undergoing a change in occupancy that would result in an increase in demand for either fossil fuel or electrical energy shall comply with this code. Where the use in a space changes from one use in Table 505.5.2 to another use in Table 505.5.2, the installed lighting wattage shall comply with Section 505.5.

101.4.5 Change in space conditioning. Any nonconditioned space that is altered to become conditioned space shall be required to be brought into full compliance with this code.

You can make the "space" comply with upgrades and "isolating" it from the rest of the building or you can make the whole building comply....Your choice...

 

[DTBarch]

I don't believe that there is a change in occupancy or use involved. The space was S-1 storage previously and will remain S-1 storage. The typical storage warehouses in the Seattle will have unit heaters spotted only where needed.

Let me paint another scenario. Let's say that you are building out a new 2,000sf office in the corner of an existing warehouse. Does the internal wall that separates the office envelope from the warehouse need continuous insulation, and if so, how is that accomplished?

 

[steveray]

Look at 101.4.5....and 101.4.3

Additions, alterations, renovations or repairs. Additions, alterations, renovations or repairs to an existing building, building system or portion thereof shall conform to the provisions of this code as they relate to new construction without requiring the unaltered portion(s) of the existing building or building system to comply with this code. Additions, alterations, renovations or repairs shall not create an unsafe or hazardous condition or overload existing building systems. An addition shall be deemed to comply with this code if the addition alone complies or if the existing building and addition comply with this code as a single building.

Exception: The following need not comply provided the energy use of the building is not increased:

1. Storm windows installed over existing fenestration.

2. Glass only replacements in an existing sash and frame.

3. Existing ceiling, wall or floor cavities exposed during construction provided that these cavities are filled with insulation.

4. Construction where the existing roof, wall or floor cavity is not exposed.

5. Reroofing for roofs where neither the sheathing nor the insulation is exposed. Roofs without insulation in the cavity and where the sheathing or insulation is exposed during reroofing shall be insulated either above or below the sheathing.

6. Replacement of existing doors that separate conditioned space from the exterior shall not require the installation of a vestibule or revolving door, provided, however, that an existing vestibule that separates a conditioned space from the exterior shall not be removed,

7. Alterations that replace less than 50 percent of the luminaires in a space, provided that such alterations do not increase the installed interior lighting power.

8. Alterations that replace only the bulb and ballast within the existing luminaires in a space provided that the alteration does not increase the installed interior lighting power.

Is the altered building going to be using more energy?

 

[mtlogcabin]

Does the internal wall that separates the office envelope from the warehouse need continuous insulation,

I don't think so since it is not part of the building thermal envelope.

and if so, how is that accomplished?

Staggered stud construction would be one way with the insulation weaved through the studs

 

[JPohling]

If the theoretical new office area is conditioned then the demising wall would need to be insulated. It is the thermal envelope between non conditioned space.

 

[mtlogcabin]

The typical storage warehouses in the Seattle will have unit heaters spotted only where needed.

It is the thermal envelope between non conditioned space.

Maybe, maybe not we don't know. Either way the wall will not be subject to wind that can hinder the performance of the insulation.

 

[jeffc]

Genarally, warehouses are designed as semi heated spaces with no wall insulation, only roof insulation. Semi heated space is defined as: heating system is freeze protection only, thermostat with a maximum setpoint capacity of 45ºF, mounted no lower than the heating, no electric resistance heating. 2012 Washington State Energy Code (https://fortress.wa.gov/ga/apps/SBCC/File.ashx?cid=2892). Semi Heated spaces need to be separated from conditioned spaces by meeting the full envelope requirements.

 

[jeffc]

Sorry, that link to the Washington State Energy Code was a little old. This is the current energy code:

https://fortress.wa.gov/ga/apps/SBCC/File.ashx?cid=2892

 

[zigmark]

DTBarch-

Read the opening sentence in Washington State Energy Code (WSEC) Section C402.1.2. "An assembly with a U-factor......equal or less than that specified in Section C402.1.2 shall be permitted as an alternative to the R-value is Table C402.2. Two questions. 1) Is the building currently heated throughout? 2) Does the new tenant intend to heat the entire building? If the answer to either of these questions in NO then the demising wall must comply with the requirements you described with the exception that is provided in the code section above. Long story short, you can always increase the wall thickness and add insulation to get the U-value below that required in Table C402.1.2 for the proposed assembly which would be U-0.055 in climate zone 4, all other occupancies, and metal framed. Here is a resource for you to check out that describes this and provides some ideas about how to attain compliance;

http://neec.net/sites/default/files/neec_codes_training/NREC-Continuous-Insulation-07-2011.pdf

Good luck!

ZIG