# Commecial Dryers used for locker room exhaust?



## klarenbeek (Feb 28, 2012)

I have a design professional who proposed the following locker room exhaust system:

New locker rooms at a local college football stadium.  Locker areas require 1310 cfm of exhaust.  There is a laundry room with 2 commercial dryers somewhat open to the  locker space--walls do not go up to structure and there is also a pass-through opening in the wall between the locker area and the laundry. Each dryer exhausts 750 cfm when running.  He wants to put a variable frequency drive on the locker room exhaust fan interlocked with the dryers.  When one dryer is running, the locker room fan would ramp down to 560 cfm, if both are running, the exhaust fan would shut off and all exhaust for the locker room space would be through the dryers.

I'm assuming he wants to do this to cut back on makeup air requirements.

Any thoughts on if this would be acceptable under the 2009 IMC?


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## cda (Feb 28, 2012)

maintance over the years?

seems like it would cost more for the electronics to be added

what if they change out the dryers??


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## Gregg Harris (Feb 28, 2012)

klarenbeek said:
			
		

> I have a design professional who proposed the following locker room exhaust system:New locker rooms at a local college football stadium.  Locker areas require 1310 cfm of exhaust.  There is a laundry room with 2 commercial dryers somewhat open to the  locker space--walls do not go up to structure and there is also a pass-through opening in the wall between the locker area and the laundry. Each dryer exhausts 750 cfm when running.  He wants to put a variable frequency drive on the locker room exhaust fan interlocked with the dryers.  When one dryer is running, the locker room fan would ramp down to 560 cfm, if both are running, the exhaust fan would shut off and all exhaust for the locker room space would be through the dryers.
> 
> I'm assuming he wants to do this to cut back on makeup air requirements.
> 
> Any thoughts on if this would be acceptable under the 2009 IMC?


Where will the makeup air for the dryers come from? IMC 504.5


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## north star (Feb 29, 2012)

*+ +*

In conjunction with Gregg Harris, ...when the exhaust fans "ramp down"

or shut off altogether,  will the HVAC units then "ramp up" to provide

make up air for the dryers?

*+ +*


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## klarenbeek (Feb 29, 2012)

There will be a makeup air unit bringing in about 2500 cfm to account for both locker room exhaust and shower/toilet exhaust.  Because the DP intends to use dryer exhaust as part of the locker room exhaust whenever the dryers are running, makeup air for the dryers will be provided through the makeup air unit.  The total exhausted air will remain constant, he just wants to change what is used to exhaust the space air.  By doing this, he can use a smaller makup air unit, 2500 cfm vs. 4000 cfm if the dryer exhaust is not also used for space exhaust required by table 403.

As far as cost, that's between the DP and customer.  Also, we only do inspections at time of initial installation or appliance replacement, not maintenance inspections throughout the life of the building.

I guess my primary question is, can air exhausted by dryers also be used as exhaust air required by table 403?


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## brudgers (Feb 29, 2012)

klarenbeek said:
			
		

> I have a design professional who proposed the following locker room exhaust system:  New locker rooms at a local college football stadium.  Locker areas require 1310 cfm of exhaust.  There is a laundry room with 2 commercial dryers somewhat open to the  locker space--walls do not go up to structure and there is also a pass-through opening in the wall between the locker area and the laundry. Each dryer exhausts 750 cfm when running.  He wants to put a variable frequency drive on the locker room exhaust fan interlocked with the dryers.  When one dryer is running, the locker room fan would ramp down to 560 cfm, if both are running, the exhaust fan would shut off and all exhaust for the locker room space would be through the dryers.    I'm assuming he wants to do this to cut back on makeup air requirements.    Any thoughts on if this would be acceptable under the 2009 IMC?


  So the entire locker room is being classified as a laundry room and meets the requirements of 508.2.5?  Can you do that in an assembly occupancy? - obviously a football locker room would be over 750 square feet and have an occupant load greater than 50 and be used for meetings before and after games (as well as half time).

  That's assuming an assembly occupancy is applied rather than going with F-1 for the laundry, of course.

  It seems to me that make-up air is the least of the design professional's problems.


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## gbhammer (Feb 29, 2012)

The MEP Engineer not Architect is trying to pull a fast one.

A locker room laundry as an F-1, really, you,ve been at hooka bar a bit to much or the leap years are catching up with you.


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## brudgers (Feb 29, 2012)

OP:  "Dryer exhaust systems shall be independent of all other systems..."

    F1: I've seen it proposed for a pizzeria because pizzas (with a capital "P") are baked...right here, in River City.


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## globe trekker (Feb 29, 2012)

comments deleted by globe trekker


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## Papio Bldg Dept (Feb 29, 2012)

gbhammer said:
			
		

> The MEP Engineer not Architect is trying to pull a fast one.A locker room laundry as an F-1, really, you,ve been at hooka bar a bit to much or the leap years are catching up with you.


This reminds me of the 'grocery store bakery' thread being an F-1.

back to the OP:  I am working from the 2006 IMC, but did you request/see the engineer's calculations for common ventilation systems as required by 403.3.2?  Otherwise, I don't see anything in the IMC that would prohibit the system they are proposing.


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## brudgers (Feb 29, 2012)

Papio Bldg Dept said:
			
		

> This reminds me of the 'grocery store bakery' thread being an F-1.    back to the OP:  I am working from the 2006 IMC, but did you request/see the engineer's calculations for common ventilation systems as required by 403.3.2?  Otherwise, I don't see anything in the IMC that would prohibit the system they are proposing.


  The exhaust system is not independent of the locker room exhaust system in the proposed scenario.


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## Papio Bldg Dept (Feb 29, 2012)

brudgers said:
			
		

> The exhaust system is not independent of the locker room exhaust system in the proposed scenario.


My mistake. I thought the OP poster noted that they could operate independently, and that the locker room exhaust would only be diminished when the clothes dryer was operational.


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## globe trekker (Feb 29, 2012)

Gas  or electric dryers (RE: Section 303.3 in the 2006 IMC)?

.


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## brudgers (Feb 29, 2012)

Papio Bldg Dept said:
			
		

> My mistake. I thought the OP poster noted that they could operate independently, and that the locker room exhaust would only be diminished when the clothes dryer was operational.


  When the showers and toilets are exhausted through the clothes dryer exhaust, it is difficult for me to see the clothes dryer exhaust as being independent.  The possible issues arising from the use of hot humid air from the showers and noxious fumes from the toilets as supply air for the dryer is left as an exercise for the reader.


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## mtlogcabin (Feb 29, 2012)

2009 IMC

504.1 Installation.

Clothes dryers shall be exhausted in accordance with the manufacturer's instructions. Dryer exhaust systems shall be independent of all other systems and shall convey the moisture and any products of combustion to the outside of the building.


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## klarenbeek (Feb 29, 2012)

I should clarify-there is a separate fan for the toilet/showers that is stand alone and not in the equation (other than makeup air requirements). Then there is a separate fan for general exhaust for the locker room.  This is the one he wants to interlock with the dryers and slow down/turn off when the dryer/s are running.  The dryers will be ducted out separately from the locker room exhaust fan in accordance with manufacturers instructions.

I know the commentary is not code, but the intent of the independent of all other systems is due to the moisture and lint that is in the dryer exhaust, to keep them from building up in the exhaust duct.  That intent is met in this design. The DP is wanting to use the dryer exhaust for a secondary purpose.  This is no different than in a commercial kitchen. A 20x20 kitchen requires 280 cfm of exhaust per table 403 based on net floor area. If a type I hood is in the kitchen exhausting 1500 cfm, I don't require an additional exhaust fan for general exhaust. The hood serves the dual purpose of exhausting the grease laden vapors and general exhaust for the space.  Remember, type I exhaust is required to be independent as well. It is an independent system, just used for more than one purpose. This is the way my CBO is leaning.


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## gbhammer (Feb 29, 2012)

mtlogcabin said:
			
		

> 2009 IMC504.1 Installation.
> 
> Clothes dryers shall be exhausted in accordance with the manufacturer's instructions. Dryer exhaust systems shall be independent of all other systems and shall convey the moisture and any products of combustion to the outside of the building.


Thanks mt. It always makes it easier when some one throws in the code reference.


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## brudgers (Feb 29, 2012)

klarenbeek said:
			
		

> I should clarify-there is a separate fan for the toilet/showers that is stand alone and not in the equation (other than makeup air requirements). Then there is a separate fan for general exhaust for the locker room.  This is the one he wants to interlock with the dryers and slow down/turn off when the dryer/s are running.  The dryers will be ducted out separately from the locker room exhaust fan in accordance with manufacturers instructions.   I know the commentary is not code, but the intent of the independent of all other systems is due to the moisture and lint that is in the dryer exhaust, to keep them from building up in the exhaust duct.  That intent is met in this design. The DP is wanting to use the dryer exhaust for a secondary purpose.  This is no different than in a commercial kitchen. A 20x20 kitchen requires 280 cfm of exhaust per table 403 based on net floor area. If a type I hood is in the kitchen exhausting 1500 cfm, I don't require an additional exhaust fan for general exhaust. The hood serves the dual purpose of exhausting the grease laden vapors and general exhaust for the space.  Remember, type I exhaust is required to be independent as well. It is an independent system, just used for more than one purpose. This is the way my CBO is leaning.


  A locker room with 100 sweating football players, plus coaches is going to generate a significant amount of warm humid air which then must be exhausted through the dryer in addition to the warm humid air from the dryer.  A piece of equipment that is most likely not designed with that sort of intake air in mind.

  IMO, the kitchen exhaust hood is somewhat different because it is not dependent upon differences in temperature and humidity in order to operate properly in the way a clothes dryer is.

  Just out of curiosity, the mechanical calcs do show that level of occupant load, don't they?


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## mtlogcabin (Feb 29, 2012)

> I should clarify-there is a separate fan for the toilet/showers that is stand alone and not in the equation (other than makeup air requirements). Then there is a separate fan for general exhaust for the locker room.
> 
> This is the one he wants to interlock with the dryers and slow down/turn off when the dryer/s are running.
> 
> The dryers will be ducted out separately from the locker room exhaust fan in accordance with manufacturers instructions.


Unless the room has an occupancy sensor to overide the dryers how do you assure there is proper ventilation for the 100 sweating football players that "may" be in the locker room when someone turns on a dryer?

I would hang my hat on the code section and tell him no. Dryers shall be seperate exhuast


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## north star (Feb 29, 2012)

*& &*





> "I would hang my hat on the code section and tell him no........Dryers shall be seperate exhuast."


*FWIW, I agree!......Cite the applicable code section to your BO and let the**onus be on him/her......That way, at least you will be [ code ] accurate,*

*without citing the Commentary.*

*& &*


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## Papio Bldg Dept (Feb 29, 2012)

I am confused, dryers can not handle warm humid air, or just the warm humid air of sweaty people?  How do these dryers function adjacent to washers?  I am confused.  Are we saying that an independent/separate exhaust is required for the clothes washer area too?


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## Frank (Feb 29, 2012)

The required air volume is being exhaused from the space.

The required outside ventilation air is being provided.

IF he does not reduce the exhaust fan or increase supply air when the dryers are running  then there will be a negative pressure pulled on the building reducing the efficiency of the dryers toilet exhuast etc.

I don't see any problem with controlling the exhuast system this way.

The supply air for the dryers is being drawn from thelocker room either way.


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## mtlogcabin (Feb 29, 2012)

Papio Bldg Dept said:
			
		

> I am confused, dryers can not handle warm humid air, or just the warm humid air of sweaty people? How do these dryers function adjacent to washers? I am confused. Are we saying that an independent/separate exhaust is required for the clothes washer area too?


A dryer is designed to handle the warm humid air that it produces. When you use additional warm humid air through the make air to the dryer it will take longer to dry the clothes and reduce the efficiency of the unit.

If he is trying to save energy he would have to prove it and I don't think he could very easily.


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## brudgers (Feb 29, 2012)

Papio Bldg Dept said:
			
		

> I am confused, dryers can not handle warm humid air, or just the warm humid air of sweaty people?  How do these dryers function adjacent to washers?  I am confused.  Are we saying that an independent/separate exhaust is required for the clothes washer area too?


  Dryers handle wet fabric by evaporation. If the air is already saturated with moisture, the dryer cannot do its job effectively. It is reasonably likely that the ambient air would be outside the operating specifications of the dryer - but if the manufacturer has a UL listing which would allow such a use and the manufacturer's literature indicates that each dryer is suitable for exhausting 1500 square feet of locker room in addition to drying fabric, I'll buy in to the design.


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## Frank (Feb 29, 2012)

brudgers said:
			
		

> Dryers handle wet fabric by evaporation. If the air is already saturated with moisture, the dryer cannot do its job effectively. It is reasonably likely that the ambient air would be outside the operating specifications of the dryer - but if the manufacturer has a UL listing which would allow such a use and the manufacturer's literature indicates that each dryer is suitable for exhausting 1500 square feet of locker room in addition to drying fabric, I'll buy in to the design.


I doubt it.  A commercial laundry plant that is not air conditioned is a lot warmer and more humid than a locker room.  Wander through a hotel laundry when they are operating.

A 750 cfm 120 pound capacity dryer has a gas input of 270 000 BTU/hr or 870 btu per pound of air 95 F 80 % rh inlet, the difference between 90 F and 40% humidity and 95 F and 80% humidity inlet air (approx 7 BTU per pound) won't be noticed.

http://www.cissell.com/adv_pdf/al11-0388.pdf


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## brudgers (Feb 29, 2012)

The small one is 1600 cfm, not 750.

    I don't see a listing for it's use as an HVAC exhaust fan.

  And commercial laundries do not typically entail the life safety considerations of assembly occupancies.


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## Frank (Mar 1, 2012)

brudgers said:
			
		

> The small one is 1600 cfm, not 750.     I don't see a listing for it's use as an HVAC exhaust fan.
> 
> And commercial laundries do not typically entail the life safety considerations of assembly occupancies.


OOps I read the metric 755 l/sec but the principle is the same that the input air entalpy is little different relative to the heating element. ratio of 7 btu / lb vs heat input of around 400.

2009 IMC

501.2.1 includes clothes dryer exhuast in the types of exhaust systems.

403.1 mandates that exhaust and supply air be about equal and 504.5 requires makeup air for dryers over 200 cfm.

Exhaust air is air removed from the space through adjacent shower room fans, kitchen hood fan, dryer exhaust, or fume hood exhaust--they are all air exhausted.

Note that in Table 403.3 locker room exhaust is required for Educational occupancy classification but the code is silent on sports and amusement locker rooms.  College sports complex would not fall under Educational as that is limited to through 12th grade. Can probably get to a requirement under public spaces toilet and shower rooms.


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## gbhammer (Mar 1, 2012)

Frank has a real good argument, I would like to see the DP's calcs to see if he and frank are on the same page.


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## brudgers (Mar 1, 2012)

Frank said:
			
		

> OOps I read the metric 755 l/sec but the principle is the same that the input air entalpy is little different relative to the heating element. ratio of 7 btu / lb vs heat input of around 400.  2009 IMC  501.2.1 includes clothes dryer exhuast in the types of exhaust systems. 403.1 mandates that exhaust and supply air be about equal and 504.5 requires makeup air for dryers over 200 cfm.  Exhaust air is air removed from the space through adjacent shower room fans, kitchen hood fan, dryer exhaust, or fume hood exhaust--they are all air exhausted.  Note that in Table 403.3 locker room exhaust is required for Educational occupancy classification but the code is silent on sports and amusement locker rooms.  College sports complex would not fall under Educational as that is limited to through 12th grade. Can probably get to a requirement under public spaces toilet and shower rooms.


  2006 IMC has locker rooms under public spaces.  But I don't buy the 0.5 cfm/sft.

  That's providing less than 1/5 the fresh air for 100 football players than is required for 100 sedentary spectators.


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## north star (Mar 1, 2012)

*=*

Some might want to assign the Locker Room as a Type "U"

Occupancy Group, ..." stables " ! [ insert the sounds of a

bunch of horses whinnying here ]    

*=*


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## Frank (Mar 1, 2012)

brudgers said:
			
		

> 2006 IMC has locker rooms under public spaces.  But I don't buy the 0.5 cfm/sft.
> 
> That's providing less than 1/5 the fresh air for 100 football players than is required for 100 sedentary spectators.


Wonder why it was removed for 09 and 12 with the rework of this table?

The code change proposals that reworked the table only gave as justification to be more like ASHRAE 62.1.


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## brudgers (Mar 1, 2012)

Frank said:
			
		

> Wonder why it was removed for 09 and 12 with the rework of this table? The code change proposals that reworked the table only gave as justification to be more like ASHRAE 62.1.


  100 sweating football players in pads perhaps?


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## Dr. J (Mar 1, 2012)

Regarding the question of how much outside air is required - the OP indicates 2009 IMC.  One of the differences with the 09 version is that outside air is not required for a locker/shower/toilet room - only exhaust.  Occupant load has nothing to do with it either - it is just a CFM/SF requirement.

Regarding whether or not the dryer will work - the design is specifically addressing the potential of exhaust affecting the dryer, so no problem there.  Frank is really close to the psycrometrics of the dryer - the inlet air RELATIVE humidity does not have that much to do with it, particularly since it is already in a conditioned space.  The inlet air will be in the 70's regardless of the relative humidity.   The difference in ABSOLUTE humidity between 78 deg/40% RH and 78 deg/90% rh is 50 vs 140 grains.  Assuming the dryer exhausts air around 120 deg (sounds like a "low" setting to me - the "cotton" setting is probably higher), it is capable of absorbing up to 550 grains.  The potential loss in capacity with 90% RH rather than 40 % rh inlet air is only about 15%.  It is unlikely a barely-conditioned commercial laundry would have a lower absolute humidity than a conditioned locker room.  Besides this is not a code issue.

Regarding separate exhausts - As far as the code is concerned, it is the same situation as a Type 1 kitchen hood or a fume hood exhausting the required room exhaust.  So deal with it.  Either prohibit both dryers and hoods from acting as general room exhaust or don't, but be consistent.  If you prohibit hoods and dryers from acting as general exhaust, at least make that known so businesses can take their tax dollars elsewhere.

Regarding good design - It is a great idea.  the challenge of how to deal with a significant piece of equipment that is used sproadically is always a tough one.  This is a good solution.


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## gbhammer (Mar 1, 2012)

And Dr. J launches from the free throw line... up...up...wow look at the distance that guy can really fly... slam dunk ladies and gentleman... slam dunk.


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## brudgers (Mar 1, 2012)

Sprinklers or one hour separation still required...which is where I came in.


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## Papio Bldg Dept (Mar 1, 2012)

gbhammer said:
			
		

> And Dr. J launches from the free throw line... up...up...wow look at the distance that guy can really fly... slam dunk ladies and gentleman... slam dunk.


If I remember correctly, Dr. J usually drove base-line and came up and under from behind the back board...either way, his dunks were aaaamazing.

Thank you Dr. J for taking to the time to clarify the operational metrics of the OP....cleared up my confusion.


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## klarenbeek (Mar 1, 2012)

We've decided to allow the system the way the DP proposed.  Because 2009IMC doesn't address non educational locker rooms, we used section 403.3 which says to use the occupancy closest to the actual occupancy, if it is not listed on the table.  The closest to a college locker room would be the locker room under educational facilities. DP had no issue with that.  In fact, a nearby private high school will also be using the facility. Our decision was based on the following:

Code states that exhaust is required, it does not address how that exhaust is accomplished. (No different than the kitchen hood scenario) How efficient the dryer is is not in the code either.

The only way the dryer exhaust is connected with the other fans is through the control wiring.  Ducting is separate so the intent of independent exhaust system for dryers is met.

The design meets both exhaust and makeup air requirements of section 403. It also allows for a smaller makeup air unit, lowering both initial cost and operational cost over the life of the building.  This college had a playoff game a couple years ago during a raging blizzard in december.  We've also had track meets postponed or cancelled in april or even early may because of snow (this facility has a track &field setup as well) so this locker room will definitely be used during times the makeup air needs to be heated.

Thanks everyone for your input.


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## north star (Mar 1, 2012)

*= =*

Is "brudgers" question about sprinklers or separation still on

the Discussion Table,  or did that point get resolved?

*= =*


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## Papio Bldg Dept (Mar 1, 2012)

brudgers said:
			
		

> So the entire locker room is being classified as a laundry room and meets the requirements of 508.2.5?  Can you do that in an assembly occupancy? - obviously a football locker room would be over 750 square feet and have an occupant load greater than 50 and be used for meetings before and after games (as well as half time).
> 
> That's assuming an assembly occupancy is applied rather than going with F-1 for the laundry, of course.
> 
> It seems to me that make-up air is the least of the design professional's problems.


I don't think it was taken off the table, we just went back to the OP.


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## beach (Mar 1, 2012)

I thought it was more about the "100 sweaty football players".........


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## brudgers (Mar 2, 2012)

beach said:
			
		

> I thought it was more about the "100 sweaty football players".........


  In a sense, yes. Dryers in a space used for assembly.


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