Guidance, not a duty

HSG47 (3rd edition, 2014) is guidance published by HSE (Health and Safety Executive). It is not a statutory instrument, and it does not create a free-standing legal duty. The document says so on its own first page: it sets out advice on avoiding injury and damage when excavating near buried services.

That distinction matters whenever someone tells you HSG47 "requires" a particular method. It does not, in the sense of imposing a binding requirement of its own. HSG47 names hand tools or vacuum excavation as ways to expose a buried service, and it stops there: it does not require either one. What actually binds a given job is the asset owner's plant-protection specification, or the duty under HSWA 1974 (Health and Safety at Work etc. Act 1974) section 2, and either of those can go further than HSG47 does.

Why it still carries weight

A document with no direct legal force still shapes what happens on site. HSE guidance is treated as a record of accepted good practice, and departing from it without a documented reason is hard to defend afterwards if something goes wrong. Read HSG47 as the working answer to what a competent contractor would do.

Once you have identified which specification actually governs the dig, see Specifying it in a scope of works for clause-level wording you can adapt to that requirement.

HSE HSG47, 3rd edition (2014), states its 500 mm rule at paragraph 108: no mechanical plant is to break ground within 500 mm of a buried service. That figure sets a boundary for machine buckets and mechanical attachments. It does not, on its own, tell you which non-mechanical method to use inside that boundary.

Paragraph 99 sets out the general position ahead of the number: where the exact position of a service is not confirmed, excavation close to it should be by hand-dug trial holes or another method that does not risk disturbing the service. Paragraph 108 narrows that to the 500 mm distance. Read together, the two paragraphs describe a zone.

What paragraph 110 adds

Paragraph 110 names the alternatives inside the 500 mm zone: hand tools, or suction (vacuum) excavation. It gives no preference between the two and sets no rule that vacuum excavation must be used. A trial hole dug by hand tools meets the same paragraph as one opened by suction excavation, provided the method does not risk damaging the service.

This is worth stating plainly because it is commonly compressed into 'HSG47 requires vacuum excavation', which the paragraph does not say. Where a scope of works or a contractor's method statement asserts that HSG47 mandates suction excavation specifically, paragraph 110 is the line to check it against.

Paragraphs 150 and 160: reinstating the ground

Paragraph 150 addresses backfilling around an exposed service: material and compaction near the service should not risk damage to it, which carries the same caution forward from excavation into reinstatement. Paragraph 160 deals with reinstating the surface itself once the service has been exposed, inspected and, where relevant, protected or repaired.

Neither paragraph specifies a technique for the excavation stage. Their relevance to a specifier is that the same non-mechanical discipline applied going down should be carried through when backfilling.

What this means for a scope of works

• The 500 mm distance in paragraph 108 is a trigger for a method change.
• Paragraph 110 offers hand tools or vacuum excavation as alternatives; a scope that specifies only one should say why, since HSG47 itself does not choose between them.
• Paragraphs 150 and 160 extend the same caution to backfilling and surface reinstatement.

Where a scope of works needs this translated into paste-in clause wording, that is covered separately: see Specifying it in a scope of works.

Two different kinds of document

HSG47 (third edition, 2014) is guidance published by the Health and Safety Executive. Guidance sets out a recommended way of working; it does not carry the force of a legal requirement in its own right, and the document says so on its own first page. An asset owner's plant-protection specification is a different kind of document. It is issued by the network operator whose asset sits in the ground, and a contractor working near that asset agrees to follow it as a condition of the job.

Where the specification requires what HSG47 only recommends

HSG47 offers a choice of methods at several points, hand tools or vacuum excavation among them, and leaves the decision to whoever is planning the work. An asset owner's specification can close that choice down for its own network, naming one method as the only one it will accept within a stated distance of its asset. Where the two disagree, the specification is what the contract enforces. HSG47 is the reasoning that sits behind it, not a substitute for it.

Where the specification goes further

An asset owner is free to set a tighter distance, a narrower list of permitted tools, or a step HSG47 never mentions, because the specification is written around one network's own risk and its own record of strikes. Reading HSG47 gives you the general position. It does not tell you what a particular gas, electricity or water network has decided to add on top of it, and a specifier who stops at HSG47 can still miss the clause the contract is actually built on.

The clause that governs a given dig sits in the asset owner's specification. Carry that clause into a scope of works once you have identified it.

HSE HSG47 (Health and Safety Executive guidance document, 3rd edition, 2014) is not law. Page 1 of the document says so directly: it sets out what the HSE regards as good practice, and a court asks whether a duty holder achieved an equivalent standard.

That does not make it optional to know. Asset owner specifications, such as a gas distribution network's plant-protection document or a water company's excavation clause, are written with HSG47 in view, and several borrow its wording directly. A buyer who has not read the paragraphs behind a specification clause is arguing from memory of what someone told them the guidance says.

Where the confusion usually starts

The line repeated most often on site is that HSG47 requires vacuum excavation within 500 mm of a buried service. The guidance does not say that. It names an excavation method restriction at that distance and offers more than one way of meeting it, and the paragraph numbers matter here because they let you check the wording yourself.

Where the difference lands is in what a contractor can propose and what you can insist on. HSG47 recommending an approach and an asset owner specification requiring it are two different levels of authority, and a scope of works needs to cite the one that actually binds the job.

The clause-level wording for stating that requirement in a scope of works, keyed to the asset owner specification rather than to HSG47 alone, is set out on Specifying it in a scope of works.