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Interpreting gas safe dig plans


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Planning a very minor trench excavation to bring in a new gas supply and water main. I've got the safe dig plan from my gas network SGN and looks fine for where I want to dig but just curious what some of the symbols which are not included in their key mean.


Assuming 250 PE means a 250mm Polyethylene pipe? So what are 8" SI, 125 FF etc?


What about the speech bubble "650943840"?







Their key:




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Most of the gas main is iron or polyethylene.  I think the FF is PF which could be pitch fibre but I didn't know that was used for gas.  SI and CI I guess iron.  ST for steel?  Maybe an experienced excavator operator could comment as they will have hit all of them over time.


Speech bubble looks like it is pointing to a valve.

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2 hours ago, Dave Jones said:

be aware those plans are +/- 100m!


Cant trust them at all,  if you are hand digging it wont be a problem if you are using a digger get someone who has done it before.


Thanks. Yes it's a tight little spot so you'd not be able to get a digger in there. 1m2 down to 900mm


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11 hours ago, Makeitstop said:


How do you know the plan is +/- 100m?



was a little tongue in cheek, they just never are 'that' accurate. ok for modern stuff but where they have transcribed from old paper plans can be literally miles out or not show anything at all when you know its there.

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