Rank: Guest 
|
Posted By Barry Cooper
At what depth would we classify a trench as a confined space. Is there a minimum depth stated anywhere, or is it just based on risk assessment
Barry
|
|
|
|
|
|
Rank: Guest
|
Posted By Bob Youel
risk assessment: as its whats going on, the environment etc that counts not just the depth of a given trench etc
|
|
|
|
|
|
Rank: Guest
|
Posted By Philip McAleenan
Barry,
Go directly to the regulations for this one. The definition of a confined space is any space... which by virtue of its enclosed nature there arises a reasonable foreseeable specified risk. And there are 5 specified risks defined in regulation 1.
The regulations are available from http://www.opsi.gov.uk/index.htm .
Regards, Philip
|
|
|
|
|
|
Rank: Guest
|
Posted By justgossip
We knock out a few excavations.
There is no specific depth recorded in legislation, there is some guidance.
Once you exceed 1 mtr depth then you are in a very hazardous area, 1 cubic mtr of earth can have a bad effect on ones health, its heavy.
Our modus, if depth exceeds 1 mtr, mandatory completion of excavation work permit by the foreman.
This targets the problem areas of the hazard whilst at the same time it will deal with confined space and work at height.
hope that helps a tad
garry
|
|
|
|
|
|
Rank: Guest
|
Posted By Phil Grace
Barry,
Not sure that wondering whether a trench is a confined space is the most important route. As previous posters have said falling/slipping earth will have a far more serious effect on ones health than any confined space issues. Build up of fumes for example is only going to be a problem if you take a portable generator down with you...! And if there is no wind to disperse fumes...
And we should bear in mind that the first prosecution for Corp Manslaughter is for a fatality following death in a collapsing trench.
Phil
|
|
|
|
|
|
Rank: Guest
|
Posted By Martyn Hendrie
Phil,
I am not sure that I agree with your statement
"Build up of fumes for example is only going to be a problem if you take a portable generator down with you...! And if there is no wind to disperse fumes..."
Fumes can be a significant problem from ground conditions (Made up ground/contamination/acid rain on chalk, etc.)
Barry is quite right to consider whether or not an excavation falls within the Confined Spaces regulations.
Setting aside trench collapse and falls issues in my opinion the CS regs would apply as soon as a person's breathing zone is within the enclosed area. (assuming a reasonable potential for fumes has been established)
|
|
|
|
|
|
Rank: Guest
|
Posted By Dave Merchant
Martyn's correct - an unprotected trench is an extremely dangerous thing, primarily from collapse but also from atmospherics. It's perfectly possible for fumes from a distant external source (generators, vehicles, etc.) to pool within an excavation, and for permeation from/through the soil or along pipes to affect the viability of the atmosphere.
Shallow trenches are statistically the biggest killers (as deep trenches are more often protected before entry). It takes less than a foot of earth on your chest to stop you breathing, and the average trench rescue takes over an hour. Do the math.
|
|
|
|
|
|
Rank: Guest
|
Posted By Jeremy Fripp
Our Excavation permit includes the following precautions (but not limited to) and typically applies to depths of 1m or more (or 4ft if in the US), a confined space permit can also be raised if deemed necessry or required by the Risk Asessment.
a. Atmosphere within the excavation tested where there is a reasonable possibility of an oxygen deficiency, combustible or other harmful contaminant exposing personnel to a hazard.
b. Adequate precautions taken to protect personnel from exposure to an atmosphere containing less than 19.5% of oxygen and/or to other hazardous atmospheres.
c. Ventilation provided to prevent personnel exposure to an atmosphere containing flammable gas in excess of 10% of the lower explosive limit of the gas.
d. Testing conducted as necessary to ensure that the atmosphere remains safe.
e. Emergency equipment, such as breathing apparatus, safety harness and lifeline and/or basket stretcher readily available where hazardous atmospheres could or do exist.
f. Personnel trained to use personal protective and other rescue equipment.
g. Safety harness and lifeline used and individually attended when entering bell bottom or other deep confined excavations.
Hope this helps
Jeremy
|
|
|
|
|
|
Rank: Guest
|
Posted By bill strachan1
Barry,
The simple answer is no, there is no specified depth to help classify an excavation as a CS and as you point out it is down to a suitable and sufficient RA.
The CS regulation does point you in the right direction, but if you are looking for a clear and simple answer to CS scenarios I'm afraid you will not find it.
Many clients have their own views on what constitutes a CS relating to excavations and IMHO unfairly demand very onerous control measures to be implemented.
I am unfortunate enough to have such a client who insist on imposing the exact same standards during the construction of a process plant where no nasy hyrocarbons and stuff will be present until the plant goes into pre-commissioning, commissioning phases. There are also additional risks with argon and nitrogen to contend with at this stage which does pose a much greater risk. At this point there is clearly a need for more stringent control measures to be implemented and imposed to prevent IDLH
|
|
|
|
|
|
Rank: Guest
|
Posted By Barry Cooper
Thanks everyone for your replies, all of which have been extremely helpful.
Risk assessment it is then
It's good to know there are many professionals out there who we can bounce ideas off, or ask questions and get answers even if it is just to confirm our own thoughts
Thanks again
Barry
|
|
|
|
|
|
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.