A scope of works that simply names the technique, 'vacuum excavation' or 'suction excavation', leaves the contractor to decide the rest: which nozzle, which card, whether a banksman stands at the point of dig, who takes the spoil away and what it becomes once classified. On ordinary groundworks that gap is manageable. Working within reach of a buried service, it is the gap where a dispute starts, either about the method used on the day or about who pays once something has been struck.

What the wording needs to fix

A scope of works for this kind of dig needs to settle each of the following in writing, against the asset type actually being worked:

• Which excavation technique applies, and to which asset
• The nozzle or lance permitted on that ground and that pipe or cable material
• The operator competence card required, and who checks it on site
• Whether a banksman is required at the point of dig
• Who owns the arisings, how they are classified, and the disposal route
• The reinstatement class the finished surface must meet

Left unstated, each of these defaults to whatever is convenient for the contractor on the day, which is not the same as whatever the asset owner's specification requires.

Where the wording comes from

Clause wording built from a plant-protection specification, HSE guidance or an industry code is a starting point for the tender document. The asset owner's specification changes between editions, and a clause copied from an older edition or from the wrong network's document will not hold up if it is queried. Before it goes into a contract, check it against the current specification for the network in question.

The per-network table on Hydro-Excavators.com | The Buyer's Guide to Vacuum, Air and Hydro Excavation in the UK sets out which specification governs which asset, which is the starting point for confirming that the clause you are pasting in still matches the document it was drawn from.

Naming the technique against the asset

A line that reads "vacuum excavation as required" leaves the choice of technique to whoever turns up on the day. A clause that holds up names the technique against the asset it is working over: suction excavation for one pipe run, air-lance excavation for a duct, water-lance excavation where the ground or the coating on the asset rules air out. The asset decides the technique before the ground is even considered, so the clause should say so in that order.

Adding the ground condition

The same asset needs different handling in different ground. A main in loose granular fill sits differently to the same main in stiff clay, and a clause that names only the asset leaves that judgement to the operator standing over the hole. Wording that carries both facts, asset type and ground condition, together with the technique they point to, gives the contractor less room to choose on the day what should have been decided at the desk.

A clause worth pasting into a tender should set out, for each asset on the job:

• The asset type and, where it affects the dig, its age or coating
• The ground condition it sits in
• The technique required for that combination
• The nozzle or lance type that goes with it

Specifying the nozzle and lance

Nozzle and lance selection follows the same two facts. A nozzle suited to one ground type can be the wrong choice against a coated or an aged asset, and a clause silent on nozzle or lance type is a clause that leaves that decision to the operator's judgement. Name it alongside the technique.

Reviewing against the current specification

Wording built this way is a starting point. Asset owners revise their plant-protection specifications, and a clause drafted against an old edition can call for a technique the current document no longer allows, or leave out a distance or a nozzle restriction the current one adds. Check the clause against the asset owner's current specification before it goes into the tender, not after, and treat any wording carried over from an earlier job the same way. The buyer's guide to vacuum, air and hydro excavation sets out where to find the specification that governs a given asset.

The legal duty is set out in the Health and Safety at Work etc. Act 1974 section 2: an employer must ensure, so far as is reasonably practicable, that a person carrying out excavation work is competent to do it. No card is named in that section. A scope of works still needs to name a card level, because that is the check a buyer can actually make on site.

Card level clause

State the card by scheme and code. For example: the operator holds a valid Construction Plant Competence Scheme card, CPCS A78 (vacuum excavation), or the National Plant Operators Registration Scheme equivalent, NPORS N021. Wording of this kind sits alongside the duty. The clause requires the card as evidence the buyer can check against the register, and the underlying duty under HSWA 1974 section 2 rests with the employer regardless of what the card shows.

CPA SAVESIG GPG1 v3 (January 2025) section 4.6 states that scheme cards should not be accepted at face value. A scope of works clause can carry that check forward by requiring the card number and expiry date to be supplied before work starts, and by reserving the right to verify it against the issuing scheme's register.

Banksman requirement

Where a banksman is specified, the clause should say what the banksman is there to do: maintaining a line of sight to the excavation, controlling vehicle movements around it, and stopping work if the operator loses sight of the tool in use. Naming the function is what lets the requirement be checked on site; naming only the role invites a body being present without doing the job the clause intended.

The clause-level wording for these two points is a starting point for a tender document, and it needs reading against the current asset owner specification before use. Details of who needs to hold what card, and the checks a site manager can run on the day, are set out on the buyer's guide to vacuum, air and hydro excavation.

Excavated material does not stay classified the same way once it leaves the hole. Spoil that comes out of a trench during suction or vacuum excavation is normally waste under the European Waste Catalogue code 17 05 04 unless it is reused on the same site without leaving it. A scope of works should say who carries that classification duty, because leaving it unstated tends to mean nobody carries it until the first load is standing in a tanker with no transfer note.

Who owns the spoil

A clause should name the party who takes ownership of arisings the moment they leave the ground: the principal contractor, the excavation subcontractor, or the client. Ownership carries the duty of care under waste law, so it should sit with whoever actually controls where the tanker goes.

• Waste classification: state that arisings are EWC 17 05 04 unless a site-specific assessment says otherwise, and who carries out that assessment.
• Carrier registration: require sight of the waste carrier's registration before the first load leaves site.
• Transfer documentation: require a signed waste transfer note for every load, retained by the party who owns the spoil.

The reuse route

Spoil does not have to leave site as waste if it can be shown to meet a reuse test. The CL:AIRE Definition of Waste Code of Practice sets out the route by which excavated material can be reused as backfill on the same site. A clause that wants to use this route should say so explicitly and name who is responsible for the assessment and the paperwork it requires, because the default position without that clause is that the material is waste.

Backfill material and reinstatement class

Backfill is a separate decision from disposal. A clause should specify the backfill material, whether that is arisings assessed suitable for reuse, imported granular fill, or another specified material, and should not leave the choice to whatever is convenient on the day.

Reinstatement itself falls under the Specification for the Reinstatement of Openings in Highways (SROH), sections S4 and S5, which set out the reinstatement classes for different road and footway categories. A scope of works should state which SROH reinstatement class applies to the specific opening, because the class determines the layer construction and materials the contractor is obliged to use, and a generic reference to "reinstate to SROH standard" without naming the class leaves that decision to the contractor doing the work.

What a clause needs to cover

• Who owns the arisings from the point they leave the excavation
• The waste classification applied and who carries out any site-specific assessment
• Whether the CL:AIRE Code of Practice route is being used, and who administers it
• The carrier registration check and the transfer note requirement
• The specified backfill material
• The SROH reinstatement class for the specific opening

Wording built along these points is a starting position. It needs checking against the asset owner's current specification for the network involved, since backfill and reinstatement requirements can differ between a gas main, a water main and a highway opening on the same job.

A tender document that specifies the excavation but not the survey behind it leaves a gap: the excavator turns up not knowing what quality level the buried services have already been located to, or whether verification by excavation was assumed in the survey brief at all. The CICES PAS 128:2022 Client Specification Guide covers the survey side of that gap in its section 4, setting out the clauses a client uses to commission a survey to a stated PAS 128:2022 quality level. The excavation clauses on this page are written to sit downstream of that.

Where the two scopes meet

PAS 128:2022 treats verification by excavation as one of the ways a quality level is confirmed on site, and that verification may be carried out by vacuum or suction excavation. An excavation clause that specifies technique, nozzle selection and reinstatement class is only complete if it also states which quality level the survey established and whether this dig is the verification step for it. Where the two scopes are written by different authors, or lifted from different templates, that link is the part most often left out.

What to check before combining them

• The quality level referenced in the excavation scope matches the level actually commissioned under the section 4 survey clauses.
• Where excavation is being used to verify a survey result, the scope states this explicitly.
• Terms used in both documents, such as the asset type and the ground condition, are described the same way, so a contractor reading both is not reconciling two vocabularies.

The clause wording set out elsewhere on this page is a starting point for the excavation side of that pairing. It still needs checking against the current asset owner specification for the network in question, in the same way the survey clauses need checking against the edition of PAS 128:2022 in force at the time.