A civil contractor asks for the services “located to Quality Level B” before an excavator arrives on Thursday. The locator traces what they can, sprays the paint and drives to the next job. The report that goes back says “services marked as per plans”. Nobody can now say which services were traced, which were read off a plan, and which were dug up and seen. Quality levels exist to close that gap.
This article summarises the quality levels in Australian Standard AS 5488, drawing on Standards Australia’s product pages and the Before You Dig Australia (BYDA) Best Practice Guide. It is a working summary for locating firms, not the standard: buy the current edition from Standards Australia for the full text, and check each client’s specification for what a job needs.
Which edition of AS 5488?
AS 5488 classifies subsurface utility information, meaning what is known about buried services. The current edition comes in two parts, both published on 24 June 2022:
- AS 5488.1:2022, Part 1: Subsurface Utility Information. How information about buried services is classified. It replaced AS 5488.1:2019.
- AS 5488.2:2022, Part 2: Subsurface utility engineering. Guidance on the engineering management of buried services.
A lot of guidance still in use, including BYDA’s Best Practice Guide from August 2022, was written against the older AS 5488-2013. The four quality levels carry through. If a client quotes a clause or a tolerance, check it against the edition they name.
The four levels at a glance
The standard grades a piece of information by how it was obtained, from D, the least reliable, up to A. BYDA’s guide describes them this way:
- Quality Level D (QL-D). Information from existing records, such as the plans asset owners send after a BYDA enquiry. These plans are often schematic and only show that an asset is there. Where no quality level is given, information defaults to QL-D.
- Quality Level C (QL-C). Records matched to what can be seen on site, such as pit lids, valves and meters. You can see the pits drawn on the plan, but the run between them is still assumed.
- Quality Level B (QL-B). The service has been detected and traced, for example with an electromagnetic locator, and its position recorded relative to features on site in three dimensions. BYDA’s guide, written against the 2013 edition, gives a QL-B electronic locate a tolerance of plus or minus 300 mm horizontally and plus or minus 500 mm vertically.
- Quality Level A (QL-A). The service has been positively identified at a point, usually by exposing it, with an absolute position recorded in three dimensions. It is the only level that counts a service as validated.
Quality Level B versus Quality Level A
This is the line most clients care about. QL-B says “we detected a service here, within a tolerance”. QL-A says “we exposed it at this point and saw it”. BYDA’s guide notes that asset owner plans sit at QL-D, that electronically located services sit at QL-B, and that services need to be potholed and exposed to reach QL-A before anyone digs near them. The preface to the 2022 Part 1 recommends absolute positioning in three dimensions through QL-A, and recognises the Geocentric Datum of Australia 2020 as the national reference for position.
So one report can, and often should, carry several levels: QL-A at the points where a non-destructive digging crew exposed a service, QL-B along the traced run between them, and QL-D for services shown on a plan that could not be detected.
A quality level has a date
The 2022 Part 1 says quality levels apply at the date the information was obtained. Ground gets dug and services get added. A QL-B mark from last month is a record of last month, so put the date against every service, not just on the cover page.
How each level is reached on site
- QL-D: read the BYDA response pack and any client records. Our guide on how to read a response pack sets out an order for it.
- QL-C: walk the site and match pits, meters, valves and marker posts to the plans.
- QL-B: trace with an electromagnetic locator, by direct connection, induction or a sonde, or scan with ground-penetrating radar (GPR), and record depth where the method gives one.
- QL-A: expose the service at a point, typically by hand digging or vacuum excavation, then survey it.
Every method has limits. An electromagnetic locator needs a conductive line, a tracer wire or a sonde inside the pipe, and a signal can jump onto a neighbouring service in the same trench. Radar depth falls away in clay and wet ground. Those limits belong in the report, beside the services they affect.
Writing quality levels into the report
For each service, record its type, quality level, the method used, depth where measured, the date, and any limitation, such as “not detected, plan location only”. Our guide to what a locating report should include has the full checklist.
How OpsChase records quality levels
In OpsChase’s utility locating software, the locator records each service on their phone as they find it: type, colour, method, depth where known and quality level, with geotagged photos of the paint and pegs and a site sketch. The report comes out grouped by quality level, from QL-A to QL-D, with methods, limitations, photos and plans in your branding. It reads the same whichever locator did the job.
AS 5488 is published by Standards Australia. OpsChase is not affiliated with Standards Australia, and its reports are structured to help you present information by quality level. Whether a job meets a client’s requirements depends on the work done on site.
Where to start
Pull three recent reports and mark each service with the level it actually reached. If most say “as per plans” with no level, start there. A field for quality level and a field for method on every service changes what a client can rely on. See pricing or book a demo.