Locating and surveying
Locating valve and hydrant caps in Vienna, Lower Austria and Burgenland as well as parts of Upper Austria and Styria
The as-built plan shows the cap; on site it is not there: tarred over, buried, built over during road works or never recorded at all. As long as it is not found, the section cannot be isolated, flushed or maintained. The cap search is therefore not a side task but a job of its own, with its own measuring technology – it comes before everything that needs an access point. Appointments on +43 (0) 2252 53169, Monday to Thursday 8:00–16:30, Friday 8:00–12:00.
What we do on site
We work through the open points in one go: surface boxes for gate valves and hydrants, manhole covers and access points. The search area is bounded beforehand from the route of the mains, alignments, gradient and neighbouring points. The point found comes back marked, on request surveyed in and photographed; exposing it is done by your municipal works department or your building contractor.
Key facts at a glance
| Methods | Magnetic locating, ground penetrating radar (GPR), electromagnetic locating of the supply pipe, sonde location, CCTV from the neighbouring manhole |
|---|---|
| Application range | Valve and fitting caps, hydrant caps, manhole covers, frames and entries, settling and inspection chambers on industrial sites, properties and in the local network |
| Duration | One to two hours, depending on the effort |
| Result format | Marking on site, location sketch and photographic report as .pdf, GPS survey points on request as .shp, .gpkg, .dxf |
| Service area | Vienna, Lower Austria and Burgenland as well as parts of Upper Austria and Styria from the Traiskirchen site |
For you as a business
For municipalities, utilities, network operators and industrial plants a vanished cap is a workflow problem: the flushing truck stands idle, the maintenance round breaks off, the section stays undocumented – and in an incident the valve that should isolate it cannot be reached. We work through the open items in one go: valve and hydrant caps, manhole covers and entries. The position comes back marked, on request surveyed and in a data set, so the same point is never searched for twice.
How the job runs
1. Enquiry and documents. You call +43 (0) 2252 53169 or write to office@cft.at. Whatever documents the operation holds help to narrow the search: as-built plan and valve register, photographs from before the road resurfacing, the note which crew last operated the cap.
2. Narrowing the search area. We do not walk the whole street: pipe route, alignments, gradient and the neighbouring points in the network define the band in which the fitting must sit. The narrower the band, the closer the search within it.
3. Locating. The first pass is magnetic: cast iron announces itself without preparation, so a crew moves quickly along the section. If there is no reading, the next method is set up instead of walking the same area magnetically a second time.
4. Marking and handover. Every cap found is marked on the surface and photographed, on request also surveyed. CFT does not open the surface – that is done by your works yard or your contractor.
Equipment and methods
Magnetic locating
Every ferromagnetic body distorts the earth’s magnetic field around it; the magnetic locator reads exactly this distortion. Cast-iron valve and hydrant caps are a small target but announce themselves – no signal needs to be applied, not even under asphalt, gravel and soil. The limits are set by the surroundings in the road space: plastic caps and concrete covers have nothing the instrument responds to, and between reinforcement, rubble and other metal the reading of such a small part drowns in the noise.
Ground penetrating radar (GPR)
The antenna sends short electromagnetic pulses downwards; at every layer boundary with different electrical properties part of them returns and is recorded as travel time. This produces a sectional image of the build-up in which concrete rings, chamber bodies and the void beneath them stand out – the cases in which the magnetic instrument stays silent. How far this reaches is decided by the ground: in cohesive or wet material the pulses do not go as deep, and under dense reinforcement the image can no longer be read.
Electromagnetic locating of the supply pipe
If the cap does not show itself, we take the route along the main: at the nearest accessible point an alternating-current signal is applied to the pipe or tracer wire, then the run is walked out on the surface. Line ends, bends and branches are the places where a fitting usually sits in a network – there the search tightens. This requires a coupling point and a continuously conductive path; on plastic pipes without a tracer wire the method is out, and in densely packed routes the signal jumps to the neighbouring line.
Sonde location
Where there is an opening, we insert a transmitting sonde, on rods or on the pushrod camera. The sonde transmits from one point; this point can be pinpointed from the surface and recorded with its depth – so even a plastic run can be followed metre by metre to the part in question. Without an accessible opening it does not work, and bends, offsets, roots and the length of the rods limit how far the sonde gets.
CCTV from the neighbouring manhole
This method serves the manholes and entries of the job, not the fitting cap: from the nearest accessible manhole the camera is driven into the section. The manhole in question shows itself from inside as an entry, connection or drop, and is surveyed on the surface via the camera sonde. It is the most unambiguous method because it shows the manhole itself. It does need an accessible neighbouring manhole and a free section – if it stands full of water, the run ends before the target.
What you receive
On site the marking counts first: it tells the crew where to open. The point is additionally recorded in a location sketch and a photographic report as .pdf. On request we survey the found points and deliver them as .shp, .gpkg or .dxf – then the cap sits in the network’s data set and not in the memory of one crew.
Costs and effort
We do not put a figure or guide price here: the size of the search area, what lies above the fitting and how many points are on the list make every job a different effort. We clarify the cost range beforehand on the phone. If a re-measurement becomes necessary, the same rule applies as for every locating job: if our measurement was wrong, you pay nothing for it; if it was right and the excavation was simply too imprecise or too shallow, we charge for the call-out.
Frequently asked questions
The cap is not in any plan. Will you still find it?
Usually yes. We do not search for the entry but for the part: the cast iron of the cap announces itself magnetically, and along the main we work our way from the last known point in the network to the one in question. If every clue is missing, what remains is the areal search with ground penetrating radar.
And if the cap is plastic, or the chamber concrete?
Not magnetically – without iron there is nothing the instrument responds to. Then ground penetrating radar and the route along the main remain: signal onto the pipe or sonde in, and follow the run to the point in question.
Do you also expose the cap you found?
No. Our work ends with locating, marking and the report. What follows – opening up, replacing the cap or cover – is done by your works yard or your contractor, on the basis of our findings.
Do we get the found points into our data set?
Yes, on request we survey the points and deliver them as .shp, .gpkg or .dxf.
And if you are wrong?
Then we come back to re-measure. If our measurement turns out to be wrong, that costs nothing. If it was right and the excavation was next to the marking or too shallow, we charge for the call-out – a measuring error by CFT is then not present.
Related services
Valve maintenance in the water network
If the caps found are to be turned and tested in the same round.
CCTV drainage survey
The step that follows the manhole found.
Cable and pipe register for GIS
If the surveyed points are to become a permanently maintained record.
Site clearance survey
If the whole area needs clarifying before the excavator, not a single point.
Instruments from Schonstedt
The magnetic locators we use for this task are also available from us.
Describe the findings.
The more precisely you describe the findings, the more directly we can go to work. Plans, readings and photos help us settle the method in advance.
What happens next
- We read your message and match the case to a method.
- We come back to you – usually with a question that shortens the appointment.
- We confirm the appointment and what it costs before anyone sets off.
Rather talk?
+43 (0) 2252 53169
Mon–Thu 8:00–16:30 · Fri 8:00–12:00
Describe your case.
Fastest by telephone – then we settle straight away which method fits and what you should prepare.
Outside office hours, write to office@cft.at.