# Two family vs three family code



## VERMA071 (Jul 31, 2018)

Hello Everyone,
I am trying to learn about codes and need info about basic differences between 2 family and three family codes. IRC code book is only for single and 2 family homes but not about three family. If I have to figure out code for 3 family ( 3 floor), what should I keep in mind as far as fire protection is concerned. Are these code going to be same for existing and new homes. If existing homes are to be converted from 2 family to 3 family, what needs to be updated or changed to bring it to the code?
Please advice.
Thx,


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## cda (Jul 31, 2018)

Converted?

Townhouse

Or
Take a House and stick three families in it??


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## VERMA071 (Jul 31, 2018)

cda said:


> Converted?
> 
> Townhouse
> 
> ...



Hi,
My brother just bought a two family house. It has basement with three floors. First and second floor is being used as 1 unit and third floor as 2nd unit. The house is in a three family zone and he is thinking of converting it into three family. I just checked the code and as per code section 711 and its exception, Horizontal assembly needs to 1 hr fire rated (If not sprinklered) and 1/2 hr rated if sprinklered.  I need advice about egress for people living on the third floor. The house is old and has old style metal fire staircase that they can access from the window. What else should I keep in my mind before we submit it for permit?
one more question.. does the house needs to have sprinkler?
Please advice.
thx,


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## cda (Jul 31, 2018)

Seems like each renter is required code compliant entrance exit

Each Sleeping rooms in the basement would require an escape window

Do not know nj codes but more than likely sprinkler required


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## VERMA071 (Jul 31, 2018)

cda said:


> Seems like each renter is required code compliant entrance exit
> 
> Each Sleeping rooms in the basement would require an escape window
> 
> Do not know nj codes but more than likely sprinkler required



Hello cda,
Thanks for your reply. Basement has no sleeping unit. Only three upper floor has the dwelling units and I am more concerned about the egress of the third floor occupants. Currently there is only one staircase that feeds all the floors. That means only one egress/exit  front door. As mentioned in my earlier post, third floor has a metal fire escape staircase t similar to the ones that we see in NY on the back side of older buildings. The occupants can access this staircase through egress window. My question is
Can this be considered a code compliant exit for the third floor or we will need to provide a regular staircase for exit?
I alsothink I don't require any separate exit for the occupant on the second floor. Please let me know if I am wrong.
Thx,


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## JCraver (Jul 31, 2018)

Sounds to me like you'll need an engineer/architect on this project - I wouldn't permit it under the residential code here.

I would suggest that you call the local building department in your City first, before you get too far in to this - they will be the ones to tell you which code applies in your jurisdiction, and what their submittal requirements / permit requirements will be.


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## fatboy (Jul 31, 2018)

Concur with JCraver, I would consider this an R-2 under the IBC. Which would mean sprinklers.


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## JBI (Jul 31, 2018)

Agree with JCraver and fatboy, you need to talk to the jurisdiction first.
I also agree that this will become an R-2 occupancy under the Building Code (permanent multiple dwelling) and would likely require sprinklers, but that decision will be up to the local jurisdiction. 
An Architect or Engineer with familiarity with NJ State and local codes is always a good idea and may be required.
Depending on exactly which Codes and what (year) Editions have been adopted, the possible answers range from 'no big deal' to 'WOW! You want to do WHAT?!"


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## Robert (Jul 31, 2018)

In addition to the fire separation of the floors, the supporting structure for the upper floor needs to be fire protected all the way to the basement foundation. That way if a fire on the ground level unit occurs, it will have some level of protection for the upper unit. Also there will be a sound transmission classification (STC) required between the floors.


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## VERMA071 (Aug 1, 2018)

Hello Everyone,

Thanks for all the good advice. I checked with the local inspector and the applicable code are IBC2015. I checked the code and I understand that we need 30 min rated floor and exterior walls as we are using sprinklers. The side walls of the house are close to the other houses so I think table 704.8 (Exterior wall opening) will apply. As the house is existing so we are thinking to add 1 type X gyp board on the ceiling and walls (Basement to third floor) to get 30 min rating as required by code. Any further advice please?
Thx,


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## cda (Aug 1, 2018)

VERMA071 said:


> Hello Everyone,
> 
> Thanks for all the good advice. I checked with the local inspector and the applicable code are IBC2015. I checked the code and I understand that we need 30 min rated floor and exterior walls as we are using sprinklers. The side walls of the house are close to the other houses so I think table 704.8 (Exterior wall opening) will apply. As the house is existing so we are thinking to add 1 type X gyp board on the ceiling and walls (Basement to third floor) to get 30 min rating as required by code. Any further advice please?
> Thx,





So what did they say about exiting requirements

Plus normally once you add sprinklers you add fire alarm


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## VERMA071 (Aug 1, 2018)

cda said:


> So what did they say about exiting requirements
> 
> Plus normally once you add sprinklers you add fire alarm



Hello cda,

we will need to provide manual fire alarm.
I did not understand your question about existing requirements. I hope you won't mind if I ask you to elaborate.
I would also request you to advice me about existing hvac ducting in the home. Do we need to provide smoke detection system for the ducts?
Thx,


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## cda (Aug 1, 2018)

Exit ing

Is it good as is or do you have to do anything to the interior stairs ??


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## cda (Aug 1, 2018)

Only if you have a hvac unit over 2000 cfm

Will each tenant have thier own hvac??


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## VERMA071 (Aug 2, 2018)

cda said:


> Only if you have a hvac unit over 2000 cfm
> 
> Will each tenant have thier own hvac??


Interior stairs


cda said:


> Only if you have a hvac unit over 2000 cfm
> 
> Will each tenant have thier own hvac??



yes, Each tenant will have their own HVAC. one in the attic for third floor and two in the basement for first and second floor. They will be penetrating rated floor so  need to be rated.
I am not sure if the stairs are rated, if not we may have to make them fire rated.
One more question...the plan arrangement of the house is that you have stair lobby and from that lobby you enter to different dwellings on all floors.my question is
Do we need a fire damper between the dwelling and the lobby so that if there is fire in the lobby or dwelling, it does not spread?
Any other issue that you guys can think of?
Please advice.
Thx,


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## VERMA071 (Aug 2, 2018)

Do you guys think we will need to submit hvac drawings prepared by mep?


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## Builder Bob (Aug 2, 2018)

Check chapter 10 for stories with one exit - it has criteria listed there that may or may not allow the condition you are trying to achieve. Also be forewarned, the fire sprinkler system required in the IBC are true NFPA 13 and 13 R fire sprinkler systems - not the NFPA 13 D or P2904 fire sprinkler systems allowed in 1 or two family dwellings & townhouses (unless amended by your state or jurisdiction)


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## cda (Aug 2, 2018)

VERMA071 said:


> Do you guys think we will need to submit hvac drawings prepared by mep?



Probably


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## VERMA071 (Aug 2, 2018)

Builder Bob said:


> Check chapter 10 for stories with one exit - it has criteria listed there that may or may not allow the condition you are trying to achieve. Also be forewarned, the fire sprinkler system required in the IBC are true NFPA 13 and 13 R fire sprinkler systems - not the NFPA 13 D or P2904 fire sprinkler systems allowed in 1 or two family dwellings & townhouses (unless amended by your state or jurisdiction)



As I mentioned earlier, second and third floor can access fire escape stair on the back through egress window. Don't you think that can be counted as asecond exit?


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## cda (Aug 2, 2018)

VERMA071 said:


> As I mentioned earlier, second and third floor can access fire escape stair on the back through egress window. Don't you think that can be counted as asecond exit?



NORMALY 
You are required a window or door in each bedroom 

So look at that first

You may not need a second exit


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## VERMA071 (Aug 3, 2018)

cda said:


> NORMALY
> You are required a window or door in each bedroom
> 
> So look at that first
> ...



yes, I don't need a second exit but only an egress window which I have. One more question regarding hvac. If we provide cooling via window AC and baseboard heating, then I think we don't need to worry about hvac calculations, ducts, dampers etc.. That will remove the need to go to the MEP engineer. Am I right?


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## cda (Aug 3, 2018)

VERMA071 said:


> yes, I don't need a second exit but only an egress window which I have. One more question regarding hvac. If we provide cooling via window AC and baseboard heating, then I think we don't need to worry about hvac calculations, ducts, dampers etc.. That will remove the need to go to the MEP engineer. Am I right?




A window in each sleeping room?

Just do not stick the ac in the required bedroom window!!!


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## VERMA071 (Dec 24, 2018)

cda said:


> So what did they say about exiting requirements
> 
> Plus normally once you add sprinklers you add fire alarm



Hello CDA,
Please advice about the difference between smoke alarms and smoke detectors. As per section 907.2.11.2, I need a smoke alarm in each sleeping room and outside sleeping rooms. As you mentioned above in one of your reply, that I might need fire alarm as we are providing sprinklers. I just want to confirm that by fire alarm, you meant smoke detectors? Please advice.
Thx,


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## cda (Dec 26, 2018)

Most ahj’s 

If you install a fire sprinkler system it has to be monitored off site, normally requires a fire alarm panel/system.

Smoke detector - normally tied into a fire alarm system 


Smoke alarm- normally a stand alone battery or 110 volt powered


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## ADAguy (Jan 18, 2019)

Have you checked with your fire insurance carrier for confirmation of your proposed use?


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