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Topic Title: Domestic Inspection Pit
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Created On: 17 February 2014 09:31 PM
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 17 February 2014 09:31 PM
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mattyatty1204

Posts: 9
Joined: 16 October 2011

Hello,

I've got a job coming up to wire a new build garage for a customer which also includes a vehicle inspection pit in the middle of the garage. I have ensured that a duct has been installed from the pit to a wall in the garage so I can install both lighting and an electrical socket but wondered what regulations govern what can and can't be installed within a pit.

In terms of lighting I was thinking of mounting some sealed florescent fitting on one of the walls in the pit either a 4ft or 2D style fitting and for use of hand power tools a 2G weatherproof socket with an double pole isolator external of the pit for when the socket isn't in use.

As I say the job is actually on a domestic property but I know it will still come under some regulations but obviously 17th doesn't directly cover this type of installation.

I am curious to see what people thoughts are on this installation as I have heard you can only use low voltage equipment but this could still cause sparks to ignite fumes etc so I want to clarify. At present I am installing to the fixtures using twin and earth as I think SWA is a slight overkill for a domestic pit installation that isn't going to be used daily or heavy plant potentially causing damage to cables etc.

Matt
 17 February 2014 09:40 PM
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Zuiko

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might be worth considering these too:
http://www.legislation.gov.uk/...997/1713/contents/made
 17 February 2014 10:06 PM
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jamieblatant

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It's got to be atex gear

My mates dad nearly died in a pit when he smashed a light and there was petrol fumes in there

Anything but bombproof is not good enough ,as for sockets that should be a zone for air tools and SELV for a hand lamp if not a battery powered one nowdays

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 17 February 2014 10:17 PM
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intrinsic4225B

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I am suprised that an inspection pit has been designed into a new-build garage as I thought pits were generally deprecated these days, in favour of a vehicle lift?

Petrol vapour is heavier than air and can flow along the ground for considerable distances before building up at low points, such as in an inspection pit, where it can then form a potentially explosive atmosphere. The same can be said for liquified petroleum gas (LPG) which may also be present as a vehicle fuel or an industrial gas.

The use of extra low voltage (ELV) is no protection against ignition - even a 1.5V AA cell can ignite an potentially explosive atmosphere under certain conditions. Nor is the use of vapour-proof luminaires solution either!
 17 February 2014 10:19 PM
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Crazycolours

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Agree - It comes under Hazardous Confined and needs careful design considerations. I certainly wouldn't be using T&E and as Jamieblatant says, expro fittings are a must.

See; Reg. 132.5.2

Edited: 17 February 2014 at 10:47 PM by Crazycolours
 18 February 2014 09:17 PM
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mikejumper

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Originally posted by: intrinsic4225B
I am suprised that an inspection pit has been designed into a new-build garage as I thought pits were generally deprecated these days, in favour of a vehicle lift?

You'd need a garage with a very high roof or one that slides over to one side James Bond style.
 18 February 2014 09:39 PM
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intrinsic4225B

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Originally posted by: mikejumper

You'd need a garage with a very high roof or one that slides over to one side James Bond style.


Yes - I maybe wasn't fully thinking of a domestic garage, but I feel it would certainly be hard to justify a pit in a new build commercial garage.
 18 February 2014 10:38 PM
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peteTLM

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Mot ramps have to be pits,.

I suppose in this situation above, they saw it as a cheap one off cost and easy to build, ie a hole in the floor with a digger.

Vehicle lifts cost £ 5000 minimum and need servicing and maintenance( and a very high roof as mentioned before)

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 20 February 2014 04:37 PM
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dickllewellyn

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I would never have thought of a pit being an explosive atmosphere. When I think back to my childhood days helping my grandad on the farm, being down the pit with open lead lights and welding up exhausts.....

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 20 February 2014 06:04 PM
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intrinsic4225B

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Dick,

A pit will not normally contain a potentially explosive atmosphere, but it could under certain circumstances, so you could be looking at at least Zone 2, depending on what other activities are undertaken in the garage:

"A place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas, vapour or mist, is not likely to occur in normal operation but, if it does occur, will persist for a short period only."

See the Health & Safety Executive publication HSG261 - Health and safety in motor vehicle repair and associated industries for further information.

Looking at things from a completely different angle - another risk that I hadn't immediately thought of that is raised in the above publication is the increasing use of refrigerants in motor vehicles and the risk of asphyxiation of these are allowed to accumulate in an inspection pit.
 20 February 2014 06:33 PM
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perspicacious

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"Looking at things from a completely different angle - another risk that I hadn't immediately thought of that is raised in the above publication is the increasing use of refrigerants in motor vehicles and the risk of asphyxiation of these are allowed to accumulate in an inspection pit."

And don't forget the MIG & TIG Argon welding gases in common use.........

Regards

BOD
 20 February 2014 09:14 PM
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slittle

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Agree with all that has been said already. I would add the a pit could and probably would also come under the confined spaces regs because of the atmosphere issues.

The workshop we use (which is local authority owned) to service our vehicles done away with all of their pits and replaced them with lots of different sorts of lifts. Worries me sometimes when I see 15 tonne fire trucks balanced on lifts or even my 3 tonne ranger hanging in the air on what appears to be very little.

Stu
 20 February 2014 10:13 PM
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Crazycolours

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Hi Stu,
Yes I agree - and mentioned that in my post #4. I would use explosive proof fittings, glands, etc. What you might have got away with 20yrs ago, wouldn't stand up in the event of any accident these days. It's your name on the Cert! If someone wants to weld, grind, etc in a pit, that's down to their ignorance, but if an explosion is the result of an electrical ignition due to incompetent design/installation faults, you are not going to see much sunshine for a while!
 21 February 2014 12:11 AM
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robuck

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Surely this must all be Atex certified including the ventilation scheme that I take it will have been installed.
 21 February 2014 12:16 PM
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rocknroll

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You non DI's are getting a bit excited here with your Workplace Regulations, a domestic client or domestic premises have no duties under these, their duties are the Building Regulations, Common Law Duty of Care and Defective Buildings Act 1972.

There are actually two issues here, the electrical installation is governed by Part P and if a new circuit is notifiable, there is no reference to Workplace Regulations so the OP's idea of T&E, plastic conduit, enclosed fittings will satisfy Part P, you can of course advise the client of the dangers of pits but at the end of the day it is their choice.

It is quite common for people who have a garage built to consider a pit, but often builders wrongly advise the client to have the garage built first, get it signed off and build the pit afterwards because this attracts the attention of the LA, whilst to most it seems like a simple hole in the ground it is a structure and notifiable under Part A, the pit must be constructed in such a manner (supporting walls and footings) so it does not cause danger to users (walls collapsing) and does not compromise the foundations of the building or neighbouring properties (walls and footings), not to mention also proximity and disturbance of services.

What the client does after you have left and certificated the job is really not your concern, if the LA was involved in notification they would advise on the various certificates the dangers of draining fuel and the dangers of fire if any welding practices were undertaken in a neighbourhood, if the client went against this advice and blew himself up or burned the premises to the ground then he would have to answer for this under Common Law and Duty of Care not the contractor if they have constructed in accordance with the Building Regulations.

Your LA will have in its arsenal construction recommendations for a pit installed in domestic garages.

regards

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"Oh! The drama of it all."
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Edited: 21 February 2014 at 12:35 PM by rocknroll
 21 February 2014 02:14 PM
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intrinsic4225B

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Looking back over the thread, I don't think anyone has mentioned specific legislation or legal duties - only the risks associated with pits in garages, regardless of their location.

I find it hard to comprehend why a installation of this type should be allowed to have lesser degree of safety simply because it is in a domestic garage as opposed to a workplace, particularly given that the risks are less likely to be fully understood by a domestic client.

Yes, there is a minimum that could be done to satisfy Part P where this applies, but I would be uncomfortable with the installation described in the orignal post, particularly since the risk could easily be mitigated by (for example) the use of Ex 'n' luminaires wired in SWA terminated in appropriate glands.

Although archaic, the Petroleum Spirt (Motor Vehicles) Regulations 1929 are still in force and do apply to domestic premises to the best of my knowledge - although if taken word-for-word would probably require every garage and garden shed in the country to have an Ex electrical installation!
 21 February 2014 02:46 PM
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betnwah

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Originally posted by: rocknroll
There are actually two issues here, the electrical installation is governed by Part P and if a new circuit is notifiable, there is no reference to Workplace Regulations so the OP's idea of T&E, plastic conduit, enclosed fittings will satisfy Part P, you can of course advise the client of the dangers of pits but at the end of the day it is their choice.

Not really - Part P requires reasonable provision for safety.

If, as the skilled and qualified professional, with an understanding of the risks from potentially explosive mixtures and electrical accessories you think it's reasonably safe, and an outcome of having exercised skill and care, to use T&E, plastic conduit & enclosed fittings then fine.

I submit though that a skilled and qualified professional, with an understanding of the risks from potentially explosive mixtures and electrical accessories would not go ahead with that, hoping that nothing went wrong, or that if it did they'd get away with saying "well I thought it was reasonably unlikely there'd be an explosion".

People use professionals to get better results than DIYing.
 21 February 2014 03:12 PM
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rocknroll

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Regarding pits, most people die or get injured from inhalation of fumes and fires caused by welding, there are very few explosions as a result of fuel.

If the consumer decides to go the LA route we will advise them of what they can and cannot do regarding a pit in a domestic garage whether it be integral, attached or detached and that will be removal of fuel in a confined space, storage of gasses etc; if the person decides not to heed this advice and suffocates, sets fire to themselves or even blow themselves up this is not our concern, our concern when giving advice is the innocent people who live, visit the property or those in immediate properties that could be affected by the persons stupidity, it is highly unlikely that an in-depth examination of electrical fittings, fire prevention arrangements or even an escape plan will be considered because it is not commercial, whether the electrical installation is to ATEX standards or Part P standards and an electrical certificate and Building Regs certificate is in place the contractor is untouchable.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Edited: 21 February 2014 at 03:22 PM by rocknroll
 21 February 2014 03:52 PM
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Zuiko

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Originally posted by: intrinsic4225B

Looking back over the thread, I don't think anyone has mentioned specific legislation


except on the very second post?
 21 February 2014 04:13 PM
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intrinsic4225B

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Zuiko,

Sorry - missed your link!

Although the principles are relevant, legal duties under the Confined Spaces Regulations 1997 are only imposed on employers and the self-employed (and probably also indirectly on employees via Heath & Safety at Work Act 1974) - so as such it does not impose legal duties on a domestic client.

See below for an example of an incident involving a fire and explosion in a pit from as recently as October 2013:

http://press.hse.gov.uk/2013/c...chanics-severe-burns/

Yes, this incident was in commercial premises but could happen anywhere where similar activities are being undertaken.
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