Particular Specification – Part 34
PARTICULAR SPECIFICATION
INFRA-RED THERMOGRAPH TESTING FOR
ROOFING AND FLOOR WATERPROOFING SYSTEM
1. Objective
To establish the integrity of the applied waterproofing membrane on the flat roof and floor surface by detecting areas of water penetration and the extent of water ingress (if any) into a building.
2. Specialist Sub-contractor
The Infra-red scanning test shall be executed at the Contractor’s own expenses in accordance with requirements specified hereafter.
3. Method
Water ingress under the waterproofing membrane to the flat roof and floor surface will cause a differential rate of thermal transmittance on the roof and floor surface. This will create a temperature differential between the dry and wet areas. The temperature differentials can be detected by an infra-red thermograph camera which converts the video signal into graphical presentations such as: spot temperatures, isotherms, temperature profiles and statistical data for analysis.
4. Equipment
Infra-red thermograph camera equipment with recording device sensitive to infra radiation and capable of operation in an approved infra-red spectrum. The equipment shall be calibrated on site before performing the infra-red scanning test.
The specification and calibration record of the equipment shall be submitted to the Architect for approval and inspection.
5. Procedure
(a) After the roofing and floor waterproofing system is constructed, seal all drain outlets on the roof and floor and/or construct dams to compartmentalize the area to be tested. All debris on the roofing and floor waterproofing system should be removed.
(b) The roof and floor area to be tested would then be fully flooded to a depth of at least 50 mm water for 24 hours.
(c) After the flooding period, all blockages on drain outlets would be removed to drain the roof and floor.
(d) At a period of 24 and 48 hours from release of the water, an infra-red scanning survey shall be undertaken (Note 1) to look for “hot-spots” which indicate areas where there had been water penetration through the waterproofing membrane.
(e) In the event of failure of the waterproofing membrane (Note 2), reseal the defective areas and perform the infra-red scanning test as steps (i) to (iv), all at the Contractor’s own expense.
(f) Infra-red scanning tests shall be carried out until the roof and floor is shown to be watertight.
6. Report
Test report of each scan is to be submitted by the infra-red scanning contractor directly to the Architect. Each report should include :
(a) The time, date and ambient temperature at the time of the infra-red scan.
(b) A detailed statement on the operation method undertaken and the equipment used.
(c) A floor plan indicating areas being tested and areas of water penetration in case of failure being detected.
(d) Photographs and colour thermogram of any locations of moisture penetration through the membrane.
(e) A temperature reference scale within the thermographic image to facilitate interpretation of the data.
Note 1 – Conditions for Infra-red scanning:
(a) The test should be carried out on a day when no rain is expected and the sky is not overcast.
(b) The roof and floor surface should be dry at the time of the test.
(c) The scanning inspection should be carried out after dark, i.e. during the cooling down phase of the building.
(d) The scanning test shall be carried out after laying of the waterproofing membrane but before the laying of protective screeds, tiles etc.
Note 2 – False result
Reflections may cause false results. When a suspected leakage area is detected, move the camera around the location and view from a different angle. If the “hot-spot” still shows up, it is likely to be an area of leakage and not a reflection.
Solar reflections and any other conditions that may affect the validity of the test (i.e. air conditioning system, heaters, cold and hot objects, etc.) must be noted in the sketch plan of the test area and stated “Not Tested”.
TC R318 - PS-34/1 -