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# Ventilation for Automated Car Wash

## Ventilation for Automated Car Wash

(OP)
Hello,

First post so bear with me on the formality. I am interning and currently working on a future detail center/automated car wash building and am running into issues with the contractor and owner about how many CO and NO2 sensors are needed and in what rooms. There are two wet detail bays, three dry detail bays, and a long ~100 ft automated wash tunnel. I had setup sensors in every bay per guidance from a sensor supplier. The issue is cost, so we are determining what is the bare minimum for removing contaminants and where CO and NO2 sensors are needed. I need codes referenced, in Iowa, and any help on what is required. I had thought that the automated tunnel needs the sensors at the least and the detail bays will not have enough car exhaust to require mechanical ventilation. Also the wash tunnel does meet the natural ventilation code, due to the wash bay doors being greater than 4% of the tunnels floor space. Tunnel has a 28' ceiling however and the doors are 12' tall.

Any help would be fantastic!

Thank you

### RE: Ventilation for Automated Car Wash

1st question: Are the car engines running during the wash cycle?

### RE: Ventilation for Automated Car Wash

(OP)
Yes, they are pulled along a belt system while in neutral. But I ended up putting my original plan of two NO2 and two CO sensors controlling two exhaust fans to the outside.

### RE: Ventilation for Automated Car Wash

I have completed numerous ones d/b. Find your local codes first. Make sure the tunnel is separate from detail areas to minimize moisture issues.
Tunnel – 28’ is mostly for trucks but can be done. I like SS positive pressure IR flanking both sides of tunnel. Angle SS reflector at 45 deg. SS tube only. IR must be total enclosed with CAI on SS from outside. SS flue. I will do 2-3 cfm/ft of exhaust connected to the line and CO&NOx sensors. I use greenheck upblast kitchen exhaust fans to keep moisture off roof. Size DF MAU to be 10% less than exhaust. I do the MAU at entry of tunnel and exhaust at exit. Steam in winter is the main item to overcome. High LAT or Cambridge work ok to fight the steam cloud at below 0 OAT. Motorized DA damper on MAU – it may freeze close in off cycle. I also do .05 cfm/ft exhaust on 24/7 to dry out tunnel and meet code. WP connections on everything. SS on MAU duct with 2 grilles and throw down the tunnel. Honeywell E2 sensors last ok and are very simple. If a very busy system look at radiant floor hydro system on the exit drive to minimize ice buildup. Waste heat boiler will work great.
Details – Exhaust at .75 cfm/ft2 or as rqd by local code. 0.05 cfm/ft2 exhaust on 24/7. CO & NOx at 3000 to 5000 ft/2 /unit unless dead zones. 100% MAU to equal exhaust. I like to use IR for heating in my climate zone 5a (Chicago). We have also done DF 80/10 MAUs on larger spaces. Unit heaters at over head doors will also work. IR will keep the drive isle dry and keep techs happy. I like the cheaper simpler positive pressure IR over the vacc systems but we have completed a few FedEx with vacc and the systems perform very nice. We did an Audi with 100% hydronic rad floors as heat, very nice but . Wet detail requires an exhaust fan to control moisture.

Good luck and think about the heating & moisture.

### RE: Ventilation for Automated Car Wash

(OP)
DrRTU, Thank you for the detailed response.

Our set up ended up being in-floor heat along the border of the wash bay, completely separate from the detail bays, 20x20 heated pads outside the entrance and exit for snow melt. We were not allowed to go through the roof of the building, not ideal i know, so we took two exhaust fans out the side wall controlled by Honeywell sensors. We have unit heaters at the entrance and exit. As far as numbers go i am not too certain. We sent it out this morning.

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