Mechanic's Pit Ventilation

[sbosecker]

I've searched the Garage Journal Forums and I've found lots of threads on Mechanic's Pits but I haven't seen any specifications on ventilation of a Mechanic's Pit.

I'm not interested in debating the merits of lift vs. pit, the liability of pits, etc.

The question for discussion is, to wit:

If a Mechanic's Pit is to be built, what are the ventilation requirements?

Searching on the interweb, I have found some guidance from the Electrical Code regarding this issue. Of course, as always, a little knowledge is a dangerous thing; hence this thread.

It seems, for commercial garages, the ventilation requirements hinge upon whether the space is considered a Major Repair Garage or a Minor Repair Garage.

For a Minor Repair Garage (...used for lubrication, inspection, engine tune-ups, replacement of parts, fluid changes... ..., brake system repairs, and similar routine maintenance work...) the requirement for ventilation seem to be, "Exhaust ventilation at a rate of 1 CFM per square foot of floor area when the building is occupied or when vehicles are parked over this area"

"The exhaust air must be taken from a point no more than 12 inches above the floor (of the pit)"

Does "Floor Area" mean the floor area of the Pit or the floor area of the room surrounding the pit?

A Major Repair Garage (with no fuels dispensed), the pit area is classified as Class I, Division 2 if there is a minimum of 6 air exchanges per hour.

The Major Repair Garage requirement is pretty clear but I'm curious if any of the members of this forum can clarify the "Floor Area" question for Minor Repair Garage.

Scott

Scott

 

[Cyberbear]

Never having any connection with "commercial" auto repair/service pits, my intuition tells me the change of air requirement involves the pit sq/ft since carbon monoxide being heavier than air tends to settle. Trapped toxic air in a pit could be problematic for those working in such confined areas and ventilation fans are a necessary thing.

 

[JonnyMac]

Hey. Im responsible for our safety systems. So requirements for our installation are gping to be different from yours as we've based our australian regulations more closely to euro regs but there are some references to US regs.
We have three 48" 4wd dynos and a few service pits. The dynos have a very comprehensive underground monitoring system which is probably way more than you need. We monitor Flammable, CO and O2 but the dynos are somewhat sealed and only accessible with removal of access plates etc and the areas are unsighted.
For our service pits we only monitor CO with a fixed sensor and I would speculate that CO would be ypur only requirement too. A Draeger sensor can be found for less than $1000US and is very easy to install. They need calibration every year. However for other hazardous tasks we use a personal monitor which can contain a combination of detection options but they are a little more expensive but very robust and work like a rechargeable phone and about the same size. As its possible to forget the portable sensor it might not be an option and fixed detection may be required.
Most garage environments are easy to assess just get a specialist in to give you a zoning or classification and to make things significantly easier have lots of ventilation and good , easy access in and out of the pit, not a ladder.
Drop me a pm if you need any help...

 

[sbosecker]

For a concise source of the ventilation information I have found so far...

Click here.

I should have included the link to this publication in my initial post.

Again, this is an explanation of the electrical code requirements. As such, I'm assuming the concern is flammables - as opposed to inert gases - and the resulting potential for excitement caused by an ignition source ...like a spark.

Scott

 

[Kevin54]

Check with Simon (HOTFR8) and his pit that he built

 

[LS6 Tommy]

From what I can tell, the requirements refer to the the floor of the pit, but I think their calculation is flawed. Normally you don't calculate air flow requirements by floor area, you use the volume of the space to be ventilated. If you think you're in the "Major Repair" category, I don't think you're going to be overly happy when you find out what the cost for a ventilation system needed to maintain 6 air changes per hour. Consider a 20'x3'x4' pit. I'll leave all the math out, but you're looking at 1440 CFM nominal, then you have to figure static pressure requirements for the duct run, which you can't do without knowing the duct requirements. If I'm wrong (which is entirely possible) and the flow is based on floor area, you're looking at 360 CFM nominal.

I'm also going to assume the system needs to be explosion proof if it's intended to exhaust combustibles. If monitoring equipment is required, it can be potentially costly, too. The CO2 & flammable vapor monitoring systems do need to be calibrated at startup & annually and depending on type, the sensors are replaced every 2-5 years. It cost $3200 to replace a CO2 & natural gas monitoring system in a boiler room that flooded last fall.

Tommy

 

[6768rogues]

You should be equally or more concerned about combustible and flammable vapors as CO. The fan and everything in the pit should be explosion proof.

 

[The Cobbler]

.......... since carbon monoxide being heavier than air tends to settle. ........

Carbon monoxide is slightly less dense than air , it basically mixes with air.

 

[Grinder Bill]

Carbon monoxide is slightly less dense than air , it basically mixes with air.

and, being a product of incomplete combustion, is combustible...

The quick lube where I get my truck oil changed has a fancy HVAC system feeding the pit; it runs on used oil... I'd suggest checking with your local building inspector to get the first hand poop.

 

[sbosecker]

From what I can tell, the requirements refer to the the floor of the pit, but I think their calculation is flawed. Normally you don't calculate air flow requirements by floor area, you use the volume of the space to be ventilated. If you think you're in the "Major Repair" category, I don't think you're going to be overly happy when you find out what the cost for a ventilation system needed to maintain 6 air changes per hour. Consider a 20'x3'x4' pit. I'll leave all the math out, but you're looking at 1440 CFM nominal, then you have to figure static pressure requirements for the duct run, which you can't do without knowing the duct requirements. If I'm wrong (which is entirely possible) and the flow is based on floor area, you're looking at 360 CFM nominal...

Tommy

Tommy,

I'm probably going to regret this but I'm going to attempt...

MATH IN PUBLIC!

20'x3'x4' = 240 cubic feet
240 cubic feet x 6 changes an hour = 1440 cubic feet per hour
1440 cubic feet per hour divided by 60 minutes in an hour = 24 CFM

If I haven't totally embarrassed myself, the actual mass flow requirements are very low.

Be gentle correcting this paper.

Best regards,

Scott

 

[sprntpshr]

It cost $3200 to replace a CO2 & natural gas monitoring system in a boiler room that flooded last fall.

Tommy

Do you happen to remember the supplier of the detection system do you? In the process of specing a similar system. Thanks

 

[LS6 Tommy]

Do you happen to remember the supplier of the detection system do you? In the process of specing a similar system. Thanks

Just a little warning, the sales engineer I dealt with is a guy named Evan Osterweil. He's a little goofy. If he ends up working with you just make sure you keep in contact with him to keep things rolling. Everything came out fine, but he can be a little slow moving sometimes.

North East Technical Sales, Inc.
215-513-1000
http://netechsales.com

Tommy

 

[sprntpshr]

Thanks Tommy, I had a look, that will get me pointed in the right direction as to what we need.

 

[LS6 Tommy]

Tommy,

I'm probably going to regret this but I'm going to attempt...

MATH IN PUBLIC!

20'x3'x4' = 240 cubic feet
240 cubic feet x 6 changes an hour = 1440 cubic feet per hour
1440 cubic feet per hour divided by 60 minutes in an hour = 24 CFM

If I haven't totally embarrassed myself, the actual mass flow requirements are very low.

Be gentle correcting this paper.

Best regards,

Scott

You didn't convert from cubic feet/minute to to cubic feet/hour. I may very easily be be wrong, too. My math:

240 cubic feet pit = 240 CFM x 60 minutes = 14,400 CFH x 6 Changes Per
Hour =86,400 CFH. Systems are rated in CFM, so 86,600 CFH/60 minutes 1440 CFM...

Tommy

 

[RossABQ]

Tommy,

I'm probably going to regret this but I'm going to attempt...

MATH IN PUBLIC!

20'x3'x4' = 240 cubic feet
240 cubic feet x 6 changes an hour = 1440 cubic feet per hour
1440 cubic feet per hour divided by 60 minutes in an hour = 24 CFM

Scott

You pass with an "A"! I would still ask your local inspector whether he will be looking for both a ~24 cfm outside air supply and an equal sized exhaust, at opposite ends of the trench. It does no good to **** in air from the garage, which is likely equally tainted with fumes.

 

[sbosecker]

You didn't convert from cubic feet/minute to to cubic feet/hour. I may very easily be be wrong, too. My math:

240 cubic feet pit = 240 CFM x 60 minutes = 14,400 CFH x 6 Changes Per
Hour =86,400 CFH. Systems are rated in CFM, so 86,600 CFH/60 minutes 1440 CFM...

Tommy

Tommy,

With the total realization that when I am most certain that I am correct, I am usually wrong... especially when I'm dealing with my spouse. Ha!

I'm pretty sure that the total volume of air in the pit is being exchanged 360 times in an hour at 1440 CFM.

1440 cubic feet per minute times 60 minutes in an hour is 86,400 cubic feet of air being moved every hour.

The pit is 240 cubic feet of volume.

86,400 cubic feet (total air moved in an hour)
divided by 240 cubic feet (the volume of the pit)
equals 360 "pit volumes" being moved in an hour.

Best regards,

Scott

 

[big.jim]

AFAIK the fan and associated equipment doesnt need to be ex rated as you are removing the possibility of a flammable atmosphere with the fan , ie the ratios are to be maintained below flammable levels of ignition and co is not flammable just harmful to life

 

[sbosecker]

Check with Simon (HOTFR8) and his pit that he built

Kevin54,

Thanks - I looked at Simon's pit build when I was searching for pit info.

Good stuff!

However, Australia is even further from Peachtree City, GA than Atlanta - a city that my neighbors and I observe with great suspicion - so I don't think anything in Simon's build would be useful as evidence for my local building department to ponder. Ha!

Best regards,

Scott

 

[sbosecker]

Hey. Im responsible for our safety systems. So requirements for our installation are gping to be different from yours as we've based our australian regulations more closely to euro regs but there are some references to US regs....
...Most garage environments are easy to assess just get a specialist in to give you a zoning or classification and to make things significantly easier have lots of ventilation and good , easy access in and out of the pit, not a ladder.
Drop me a pm if you need any help...

JonnyMac,

Thanks! I'm trying to walk into the local building department with an idea of what's required for something like this.

Ventilation seems like an obvious issue so I'm starting with that.

We'll see what happens.

Best regards.

Scott

 

[Stuart in MN]

Again, this is an explanation of the electrical code requirements. As such, I'm assuming the concern is flammables - as opposed to inert gases - and the resulting potential for excitement caused by an ignition source ...like a spark.

Scott

You're correct in that the regulations in the National Electric Code (which is NFPA 70) relate to explosive gases or vapors that may enter the pit. The life safety stuff for carbon monoxide are covered in other sections of the NFPA. I looked them up once but don't recall which section - if you have access to a set of NFPA manuals, I think it's either section 30A or section 88B.

Getting back to the NEC/NFPA 70, any wiring in the pit for lights or receptacles should be rated for a Class 1, Division 1 area (where explosive gases or fumes are likely to be present.) The area from floor level up to 18 inches above the floor should be rated for Class 1, Division 2 (where explosive gases or fumes may be present.) However, the thing about the NEC is it only specifically mentions garage pits used in commercial repair garages, there's no mention that I've been able to find that covers residential or home use.

One other thing - strictly speaking, any electrical tools like trouble lights or electric drills should also be rated for the space. This would be a good reason to use air tools instead of electric.

 

[sbosecker]

You're correct in that the regulations in the National Electric Code (which is NFPA 70) relate to explosive gases or vapors that may enter the pit. The life safety stuff for carbon monoxide are covered in other sections of the NFPA. I looked them up once but don't recall which section - if you have access to a set of NFPA manuals, I think it's either section 30A or section 88B.

Stuart,

NFPA?

Best regards,

Scott

 

[Stuart in MN]

NFPA = National Fire Protection Agency. They have a huge set of codes and standards (the books take up about four feet of shelf space) for all kinds of buildings for all kinds of purposes.

Here's the index of sections: http://www.nfpa.org/codes-and-standards/document-information-pages You can view the various sections online (look on the left side of the page where it says 'free access') but you have to create a login to get there. You also may be able to find a set of books at a local library.

 

[sbosecker]

NFPA = National Fire Protection Agency. They have a huge set of codes and standards (the books take up about four feet of shelf space) for all kinds of buildings for all kinds of purposes.

Stuart,

Thank you very much!

This should put me to sleep tonight. Ha!

I've already found a little more information - from another source I think - that addresses ventilation.

Here's the source:

https://www.inkling.com/read/nfpa-fire-code-handbook-harrington-2012/chapter-30/30-2-repair-garages

30.2.6.4

Pits, belowgrade work areas, and subfloor work areas shall be provided with exhaust ventilation at a rate of not less than 1 ft3/min/ft2 (0.3 m3/min/m2) of floor area at all times that the building is occupied or when vehicles are parked in or over these areas. Exhaust air shall be taken from a point within 12 in. (0.3 m) of the floor. [30A:7.4.5.4]

Paragraph 30.2.6.4 addresses ventilation of pits, below-grade work areas, and subfloor work areas. Experience with these facilities shows that a vehicle seldom has a leak in its fuel system or fuel tank. When a leak is present, the odor of the fuel is obvious and the vehicle is removed from the building. The Technical Committee on Automotive and Marine Service Stations reviewed ventilation rates required by NFPA 30, Flammable and Combustible Liquids Code; NFPA 88B, Standard for Repair Garages; and NFPA 70 ®, National Electrical Code®, as well as several mechanical codes. The committee also reviewed the calculation procedure to determine dilution rates, which are described in the NFPA Fire Protection Handbook® Using this method, a spill of about 1⁄2 liter (about 1 pint) of gasoline would require 800 ft3 to 1050 ft3 (23 m3 to 30 m3) of air to dilute the mixture to 25 percent of the lower flammable limit, the point that is traditionally considered minimally safe. Based on this result, the technical committee determined that the traditionally accepted ventilation rate required by NFPA 30 and other codes — 1 ft3 per minute per ft2 (0.3 m3 per minute per m2) of floor area — would be more than adequate. This ventilation rate provides at least six air changes per hour, based on an assumed ceiling height of 10 ft (3 m), without causing excessive heat loss in the winter months.

Make-up air supplied in excess of that which is actually exhausted should be avoided, because any flammable vapors that are released might be driven above the exhaust duct inlets and into overhead electrical fixtures. Usually, sufficient make-up air is provided by normal leakage around service bay doors.

The user is cautioned that the ventilation rate specified is adequate for small spills only. A larger spill would require much more ventilation capacity; for example, 6300 ft3 to 8400 ft3 per minute per ft2 (180 m3 to 240 m3 per minute per m2) for a 1 gal (3.8 L) spill. Therefore, compliance with Chapter 9 of NFPA 30A is just as important in these facilities as it is for a traditional service station.


Again, a little knowledge is a dangerous thing so more reading is required.

Best regards,

Scott

 

[kbs2244]

So, It boils down to "What are you comfortable with."
Personally, I favor the "positive pressure out of the hole" concept.
Get a good volume fan routed down to the bottom of the pit so all the fumes go over the floor level and away and you are literally "Covered" by the previous planning.

Of course, that assumes you thought about fumes before building the shop.

 

[Grinder Bill]

AFAIK the fan and associated equipment doesnt need to be ex rated as you are removing the possibility of a flammable atmosphere with the fan , ie the ratios are to be maintained below flammable levels of ignition and co is not flammable just harmful to life

Carbon monoxide is highly flammable; it's rated as a 4 (highest risk) under NFPA 704:

"Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily "

 

[sbosecker]

NFPA = National Fire Protection Agency. They have a huge set of codes and standards (the books take up about four feet of shelf space) for all kinds of buildings for all kinds of purposes.

Here's the index of sections: http://www.nfpa.org/codes-and-standards/document-information-pages You can view the various sections online (look on the left side of the page where it says 'free access') but you have to create a login to get there. You also may be able to find a set of books at a local library.

Stuart,

You seem familiar with this information...

Do you happen to know if the ventilation for Minor Repair Garage pits is based on the square feet of the pit floor or the square feet of the shop floor around the pit?

Best regards,

Scott

 

[Stuart in MN]

I looked at article 511 in the NEC. It is a little confusing since there are different requirements for Major Repair Garages and Minor Repair Garages. Note that the six air changes per hour mentioned earlier is for Major Repair Garages, and not for Minor Repair Garages.

Here's what it says for Minor Repair Garages (this is article 511(D)(1), from the 2008 edition which is what I have here at home, my copy of the latest edition is at the office. I don't know if there were any changes to this section in the latest edition.)

****

Floor areas in minor repair garages without pits, below grade work areas, or subfloor work areas shall be unclassified. Where floor areas include pits, below grade work areas, or subfloor work areas in lubrication or service rooms, the classifications in (a) or (b) shall apply.

(a) Ventilation Provided. The entire floor area shall be unclassified where there is mechanical ventilation providing a minimum of four air changes per hour or one cubic feet per minute of exchanged air for each square foot of floor area. Ventilation shall provide for air exchange across the entire floor area, and exhaust air shall be taken at a point within 0.3m (12 in.) of the floor.

(b) Ventilation Not Provided. The floor area up to a level of 450mm (18 in.) above any unventilated pit, below grade work area, or subfloor work area and extending a distance of 900mm (3 ft) horizontally from the edge of of any such pit, below grade work area, or subfloor work area, shall be classified as Class 1, Division 2.

 

[R68GTO]

It is the entire floor area of the shop, not just the pits. We just had a full engineering study done in our existing shop to see what it takes to meet code for servicing CNG vehicles. In the process of doing that, they informed us that our shop did not meet NFPA code for gasoline/diesel/propane because we had iginition sources within 18" of the floor. They are telling us we have to raise the 110v outlets that are located in the office above the 18" min. Our ventilation system is designed appropriately and does air change the entire shop.

 

[sbosecker]

****

Floor areas in minor repair garages without pits, below grade work areas, or subfloor work areas shall be unclassified. Where floor areas include pits, below grade work areas, or subfloor work areas in lubrication or service rooms, the classifications in (a) or (b) shall apply.

(a) Ventilation Provided. The entire floor area shall be unclassified where there is mechanical ventilation providing a minimum of four air changes per hour or one cubic feet per minute of exchanged air for each square foot of floor area. Ventilation shall provide for air exchange across the entire floor area, and exhaust air shall be taken at a point within 0.3m (12 in.) of the floor.

(b) Ventilation Not Provided. The floor area up to a level of 450mm (18 in.) above any unventilated pit, below grade work area, or subfloor work area and extending a distance of 900mm (3 ft) horizontally from the edge of of any such pit, below grade work area, or subfloor work area, shall be classified as Class 1, Division 2.

Stuart,

Thank you.

It takes a Philadelphia lawyer to figure this stuff out. I was assuming the "Floor" requirement was either for the shop floor or the pit floor.

If I am understanding this correctly, "Floor" in this case is the shop floor AND the pit floor. I hadn't considered that interpretation. Partly because of the "...exhaust air shall be taken at a point within .3 m (12 in.) of the floor..." I had to assume that floor was the pit floor.

The way it is worded - to me - the ventilation could be anywhere on the shop floor and not have to be in the pit, within 12 inches of the pit floor, to be in compliance.

I'm pretty sure that is not what is intended here if a pit is present.

Best regards,

Scott

 

[sbosecker]

It is the entire floor area of the shop, not just the pits. We just had a full engineering study done in our existing shop to see what it takes to meet code for servicing CNG vehicles. In the process of doing that, they informed us that our shop did not meet NFPA code for gasoline/diesel/propane because we had iginition sources within 18" of the floor. They are telling us we have to raise the 110v outlets that are located in the office above the 18" min. Our ventilation system is designed appropriately and does air change the entire shop.

R68GTO,

Your office area was considered a part of the shop?

Best regards,

Scott

 

[Stuart in MN]

Stuart,

The way it is worded - to me - the ventilation could be anywhere on the shop floor and not have to be in the pit, within 12 inches of the pit floor, to be in compliance.

I'm pretty sure that is not what is intended here if a pit is present.

Best regards,

Scott

This is getting out of my area of expertise, but I think you put the exhaust fan in an exterior wall somewhere and then you also have to have an air intake duct that brings fresh air into the pit. That way, you have airflow pulling any fumes or vapors up and out of the pit.

I looked around online and found this website: http://www.heac.no/garage_pit.php It's a design firm in Norway and they have some example drawings for a garage pit design. Of course, the drawings are in Norwegian but they show how air intake pipes are routed into the bottom of the pit.

 

[Stuart in MN]

R68GTO,

Your office area was considered a part of the shop?

Best regards,

Scott

If there's an open doorway between the office and shop, and their floor levels are the same, both areas will have the same hazard rating.

 

[sbosecker]

Here's what it says for Minor Repair Garages (this is article 511(D)(1), from the 2008 edition which is what I have here at home, my copy of the latest edition is at the office. I don't know if there were any changes to this section in the latest edition.)

****

Floor areas in minor repair garages without pits, below grade work areas, or subfloor work areas shall be unclassified. Where floor areas include pits, below grade work areas, or subfloor work areas in lubrication or service rooms, the classifications in (a) or (b) shall apply.

(a) Ventilation Provided. The entire floor area shall be unclassified where there is mechanical ventilation providing a minimum of four air changes per hour or one cubic feet per minute of exchanged air for each square foot of floor area. Ventilation shall provide for air exchange across the entire floor area, and exhaust air shall be taken at a point within 0.3m (12 in.) of the floor.

(b) Ventilation Not Provided. The floor area up to a level of 450mm (18 in.) above any unventilated pit, below grade work area, or subfloor work area and extending a distance of 900mm (3 ft) horizontally from the edge of of any such pit, below grade work area, or subfloor work area, shall be classified as Class 1, Division 2.

Stuart,

I'm not trying to shoot the messenger here... I'm re-reading this and I'm just trying to figure out the rationale behind the Minor Repair Garage ventilation requirements.

If a Minor Repair Garage has no pit (or other lower level stuff) there is no need for any ventilation and it will still be unclassified space.

However, if a Minor Repair Garage has a pit (or other lower level stuff) NOW the stipulation is that the entire shop floor or volume figures into the ventilation in order for the shop to remain unclassified space?

What's up with that? What is going on in that pit that changes the entire dynamic of a Minor Repair Garage?

Since a "no pit shop" requires no ventilation, I could see the required ventilation for a "shop-with-a-pit" being based on the volume of air in the pit but instead the entire shop floor drives the "ventilation required" equation?

That's a puzzler...

There's probably a reason for this apparent ventilation paradox but, at the moment, it escapes me.

Best regards,

Scott

 

[LS6 Tommy]

Tommy,

With the total realization that when I am most certain that I am correct, I am usually wrong... especially when I'm dealing with my spouse. Ha!

I'm pretty sure that the total volume of air in the pit is being exchanged 360 times in an hour at 1440 CFM.

1440 cubic feet per minute times 60 minutes in an hour is 86,400 cubic feet of air being moved every hour.

The pit is 240 cubic feet of volume.

86,400 cubic feet (total air moved in an hour)
divided by 240 cubic feet (the volume of the pit)
equals 360 "pit volumes" being moved in an hour.

Best regards,

Scott

See, I told you I might be wrong... don't know where I fudged the math. It's never been my strong point, but boy, I thought I was at least close to being right...

Tommy

 

[Stuart in MN]

Stuart,

I'm not trying to shoot the messenger here... I'm re-reading this and I'm just trying to figure out the rationale behind the Minor Repair Garage ventilation requirements.

If a Minor Repair Garage has no pit (or other lower level stuff) there is no need for any ventilation and it will still be unclassified space.

However, if a Minor Repair Garage has a pit (or other lower level stuff) NOW the stipulation is that the entire shop floor or volume figures into the ventilation in order for the shop to remain unclassified space?

What's up with that? What is going on in that pit that changes the entire dynamic of a Minor Repair Garage?

Since a "no pit shop" requires no ventilation, I could see the required ventilation for a "shop-with-a-pit" being based on the volume of air in the pit but instead the entire shop floor drives the "ventilation required" equation?

That's a puzzler...

There's probably a reason for this apparent ventilation paradox but, at the moment, it escapes me.

Best regards,

Scott

That I can't answer - some committee made the decision.

 

[big.jim]

so a shop with a sunken lift is classed as having a pit and therefore needs ventilation

 

[LS6 Tommy]

I get where I messed up, but it lead me to some other weird thoughts. The code states "Exhaust ventilation at a rate of 1 CFM per square foot of floor area when the building is occupied or when vehicles are parked over this area" and "6 air changes per hour". I know we kind of agreed it should be based on the volume of the pit and not the area, so I'll do it like that.

Our assumed 240 cubic foot pit would require 240 CFM as per the code. That would be 1 air change. No problem, I get that. The code also states 6 CPH, so that's a total of 1440 Cubic Feet of air that must be moved in 60 minutes. Got it. Here's my new confusion. 1440 Cubic Feet of air moved/60 minutes is 24 CFM, which is only one tenth the minimum requirement of 240 CFM... Which one prevails??


Tommy

 

[R68GTO]

R68GTO,

Your office area was considered a part of the shop?

Best regards,

Scott

Correct. Same floor level so it is part of the shop.

 

[HOTFR8]

Check with Simon (HOTFR8) and his pit that he built

Kevin54,

Thanks - I looked at Simon's pit build when I was searching for pit info.

Good stuff!

However, Australia is even further from Peachtree City, GA than Atlanta - a city that my neighbors and I observe with great suspicion - so I don't think anything in Simon's build would be useful as evidence for my local building department to ponder. Ha!

Best regards,

Scott

Scott, If you do what I did but double the size of everything you would be OK, also set it up so the ventilation comes on for a time before you access the pit.

I found plenty of rules on the internet but every location in the world will look at things very differently. Make sure any power you have in the pit is spark proof.