Conversion of 14-stories commercial building (bank) into residential building.

[UrielMuc]

Hi everyone,

This is my first approach to the IECC code, so I have some follow up questions.

I am working on a project for an existing 14-story building that was previously in commercial (bank) use and had been unoccupied for 10 years. I have seen that in section R505 "Change of Occupancy or Use" it mentions that if a space is converted to dwelling units it must meet code.

This building will be converted to a water source heat pump.

My question is: Since it has been unused for 10 years, should this be considered a change of use of occupancy or should it be considered an alteration?

On the other hand, if the envelope and glazing of the project have not been modified, can the reference model maintain the same values of the construction systems of the existing building or should they stick to the values of a new building?

I would appreciate your help to have a better approach to the standard.

 

[classicT]

Very much a change of use.

What version of the IECC are you using? You registered out of Mexico

 

[Yikes]

Welcome to the forum!
See IECC chapter C202 definition of “change of occupancy”. In my opinion, the fact that the building was vacant/unused for many years is irrelevant. The only relevant issue is: what do the city records say was its previously permitted occupancy?

By the way, where is this project located? What are the other applicable codes besides the energy codes?

 

[UrielMuc]

Very much a change of use.

What version of the IECC are you using? You registered

We are using the IECC 2021 version and the project is in the United States.

 

[UrielMuc]

Welcome to the forum!
See IECC chapter C202 definition of “change of occupancy”. In my opinion, the fact that the building was vacant/unused for many years is irrelevant. The only relevant issue is: what do the city records say was its previously permitted occupancy?

By the way, where is this project located? What are the other applicable codes besides the energy codes?

We are using the IECC 2021 version and the project is in the United States.

 

[classicT]

Here is what the 2021 IECC says for change of occupancy or use:

2021 IECC - C505.1 General​

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 C405.3.2(1) or C405.3.2(2) to another use in Table C405.3.2(1) or C405.3.2(2), the installed lighting wattage shall comply with Section C405.3. Where the space undergoing a change in occupancy or use is in a building with a fenestration area that exceeds the limitations of Section C402.4.1, the space is exempt from Section C402.4.1 provided that there is not an increase in fenestration area.
Exceptions:

1. Where the component performance alternative in Section C402.1.5 is used to comply with this section, the proposed UA shall not be greater than 110 percent of the target UA.
2. Where the total building performance option in Section C407 is used to comply with this section, the annual energy cost of the proposed design shall not be greater than 110 percent of the annual energy cost otherwise permitted by Section C407.3.

 

[steveray]

So to sum this up a bit....If the apartments will use more energy than the office building, the entire building needs to meet the current energy code....Windows, doors, insulation, air sealed outlets, all of it...Unless you can nail one of the exceptions...

Meant to quote CT here but missed it.....

 

[ICE]

If the apartments will use more energy than the office building, the entire building needs to meet the current energy code.

There is a looming burst bubble in the commercial office space sector. Downtowns in cities are becoming vacant and repurposing the space to residential is a viable solution. Relaxing energy and building codes in favor of staving off a recession makes sense.

 

[e hilton]

So to sum this up a bit....If the apartments will use more energy than the office building,

Interesting question. If the building has been vacant for 10 yrs, good chance it is 20+ yrs old. Relamping with LED’s should cut energy use there. Maybe installing a new more efficient hvac system. But i wonder about changing from business use daytimes 5 or 6 days a week, to residential hours … which would use more?

 

[classicT]

Interesting question. If the building has been vacant for 10 yrs, good chance it is 20+ yrs old. Relamping with LED’s should cut energy use there. Maybe installing a new more efficient hvac system. But i wonder about changing from business use daytimes 5 or 6 days a week, to residential hours … which would use more?

Agreed. Definitely possibilities to be had if one wanted to do the energy modeling. That said, unlikely that the supporting utilities would have historical data from 10+ years prior. Thus, modeling existing and proposed would likely be necessary.

 

[steveray]

There is a looming burst bubble in the commercial office space sector. Downtowns in cities are becoming vacant and repurposing the space to residential is a viable solution. Relaxing energy and building codes in favor of staving off a recession makes sense.

Not to the energy A@#$%^&*....

 

[steveray]

There is a looming burst bubble in the commercial office space sector. Downtowns in cities are becoming vacant and repurposing the space to residential is a viable solution. Relaxing energy and building codes in favor of staving off a recession makes sense.

I call that the "strip mall change of use permit killer" code section....I get what they are trying to accomplish...I just also understand what they are accomplishing....

 

[mtlogcabin]

the entire building needs to meet the current energy code....Windows, doors, insulation, air sealed outlets, all of it.

I disagree.

R501.1.1 General.​

Except as specified in this chapter, this code shall not be used to require the removal, alteration or abandonment of, nor prevent the continued use and maintenance of, an existing building or building system lawfully in existence at the time of adoption of this code. Unaltered portions of the existing building or building supply system shall not be required to comply with this code.
apps

​

 

[classicT]

I disagree.

R501.1.1 General.​

Except as specified in this chapter, this code shall not be used to require the removal, alteration or abandonment of, nor prevent the continued use and maintenance of, an existing building or building system lawfully in existence at the time of adoption of this code. Unaltered portions of the existing building or building supply system shall not be required to comply with this code.
apps

Except as specified in this chapter.... see C505.1.

 

[Yankee Chronicler]

My question is: Since it has been unused for 10 years, should this be considered a change of use of occupancy or should it be considered an alteration?

Both. A change from business (bank offices) to residential is a change of use and occupancy classification. I assume the floor plans will have to change to accommodate dwelling units, so it is also an alteration. Most likely it will be a Level 3 alteration, if compliance with the IEBC is going to be by the work area method.

Is your question really about the IECC (the International Energy Conservation Code), or are you asking about the IEBC (the International Existing Building Code)? Both apply, of course, but the question as asked seems to be more pertinent to the IEBC.

 

[mtlogcabin]

I assume the floor plans will have to change to accommodate dwelling units, so it is also an alteration.

No under the IEBC a change of occupancy would be under section 506 or Chapter 10 of which none of them send you to the energy code.

This will probably help with meeting one of the exceptions if he can find the energy usage from 10 years ago to compare with he projected use.

TABLE C405.3.2(1)
INTERIOR LIGHTING POWER ALLOWANCES:
BUILDING AREA METHOD

c. Dwelling units are excluded. Neither the area of the dwelling units nor the wattage of lighting in the dwelling units is counted.

​

 

[Yankee Chronicler]

Interesting question. If the building has been vacant for 10 yrs, good chance it is 20+ yrs old. Relamping with LED’s should cut energy use there. Maybe installing a new more efficient hvac system. But i wonder about changing from business use daytimes 5 or 6 days a week, to residential hours … which would use more?

Business (offices) would probably use more, but during daytime peak hours, whereas residential would probably use more energy at night than during the day. (Unless it's elderly housing.)

 

[e hilton]

It’s a good idea … repurposing vacant buildings … possibly creating affordable housing … providing shelter for the homeless. But if it’s not managed correctly they will be creating a lot of high rise housing projects that will devolve into slums.

 

[steveray]

No under the IEBC a change of occupancy would be under section 506 or Chapter 10 of which none of them send you to the energy code.

This will probably help with meeting one of the exceptions if he can find the energy usage from 10 years ago to compare with he projected use.

TABLE C405.3.2(1)
INTERIOR LIGHTING POWER ALLOWANCES:
BUILDING AREA METHOD

c. Dwelling units are excluded. Neither the area of the dwelling units nor the wattage of lighting in the dwelling units is counted.

​

The energy code sends you to the energy code now:

Section C505 Change of Occupancy or Use​

C505.1 General

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 C405.3.2(1) or C405.3.2(2) to another use in Table C405.3.2(1) or C405.3.2(2), the installed lighting wattage shall comply with Section C405.3.

Lighting is the easiest thing to comply with now anyway so the dwelling units probably will work anyway....But in a COU, the lighting has to comply with new code (new code with exceptions that is)....

Prescriptive IEBC sends you back to the building code for COU, which in turn sends you to IBC I agree that Ch 10 does not specifically, but:

C501.1 Scope​

The provisions of this chapter shall control the alteration, repair, addition and change of occupancy of existing buildings and structures.