Ground Penetrating Radar (GPR) is an ideal technique for locating chimney flues in buildings.
GPR is an entirely non-destructive and non-invasive technology (NDT), requiring only access to the surfaces of the walls to be surveyed. A GPR chimney flue location survey will cause no damage to the building and there is no requirement to drill or otherwise use intrusive investigation methods.
Because GPR is a low impact technique causing minimum disruption, GPR chimney flue location surveys can be conducted on buildings that are still in use or otherwise occupied.
How a chimney flue location survey works?
Our engineers will attend site and using our advanced hand held GPR equipment, perform a comprehensive investigation of every wall to be surveyed. Our equipment must travel across the surface whilst remaining in direct contact at all times, this will be repeated to achieve full coverage of the wall. To this end we will require unrestricted access to all of the walls in question. Where possible we will also collect additional information such as the number of chimney pots on the stack, the location of the stack, and the number and locations of the fireplaces.
GPR data collected on-site is saved for processing and interpretation back in the office.
Once in the office we import the information saved on-site into our specialised GPR post-processing software, which allows us to locate the paths of the flues through the walls and interpret the GPR data. GPR data processing and interpretation is a specialised task which may take a few days to complete.
After the GPR data processing is complete, a drawing will be compiled in CAD showing the locations of the chimney flues on an elevation plan of the building. All of our projects are subject to a final quality control and then the results will be issued to the customer. This type of drawing is our typical deliverable.
On-site mark out chimney flue location surveys
On some occasions, we are asked to mark the locations of the chimney flues directly on the walls. This is not as ideal as a traditional chimney flue location survey with post processing, because it is necessary to rely on on-site information without the use of advanced processing techniques, but it is sometimes necessary to provide immediate guidance as to where the flue is located, and where it is not (for example immediately prior to other invasive works).
In this case our deliverable will be the marks on the wall. On-site mark out is a useful type of survey, but we recommend the production of a drawing where possible.
What is a chimney flue?
A flue is the term that refers to the passage or void through which exhaust gasses from a fire, boiler, or other combustion device are vented to the outdoors. Modern flues are metal pipes from which the fumes from a heating device such as a boiler exit the building, they will often be identified by a short pipe which travels (often horizontally) through the wall.
In properties with a fireplace, a chimney flues will be built into the chimney breast, this allows the gasses to escape vertically through the roof. If a property has multiple fireplaces, such as those of the Victorian and Edwardian era, then multiple flues may be built into the walls: providing an individual pathway from each fireplace to the chimney stack on the roof. The chimney stack is the name given to the row of chimney pots above the roofline, and there should typically be one chimney flue and chimney pot for each fireplace.
A GPR chimney flue location survey will allow you to trace the pathway of each flue from fireplace to stack.
Why locate chimney flues?
There are many reasons to locate chimney flues, you may wish to demolish a wall in order to connect adjoining rooms or apartments, drill into or through a wall, or install a fire or other combustion device and be looking for a convenient route to expel the exhaust gasses. Disused chimney flues also make ideal routes for cables and pipes to travel through a building and may be used for this purpose.
Damage to an active chimney flue can cause toxic gasses to escape inside the building with serious health implications including death, so it makes sense to take precautions.
If you need to locate a chimney flue, contact KB GPR Surveys for a quotation at firstname.lastname@example.org