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How exactly the light can detect the leak through duct? do you think its possible to use this kind of test method for shaft's duct?
- Prefer to make at night after sunset, if not you have to close both ends.
- Prepare a good movable lighting source.
- Inspector should stay at one end and look inside the duct.
- Another person should carry the lighting source and passing over all connections he has to focus on the corners.
- If inspector see any light inside the duct that means that is not good connection so you have to add more silicon to close the gap.
- There is an acceptable percentage for leakage take it into your consideration.
- this method is applicable for all ducts even the shafts.
Light test for duct leakage is the most common test and very authentic but there is a procedure to take into the consideration.
1. outside should be dark enough so u can hardly see things than turn on the light in the duct and move it so you are sure that every angle is ok.
2. dont forget to check the duct from above as well since many inspectors check ducts from side and below.
3. for shafts its better to check duct before installation inside the shaft otherwise there is risk of leakage since test cannot be done exactly inside the shaft but it is acceptable
Light test is commonly used to identify the leakage of duct, as we ll use this procedure for Commercial and residential buildings only but i think this method is not useful in clean room ducts ( pharmaceutical).
To do this test requires the Sufficient light and out side should be dark, the selection of light depends on the length of the ducts. Ex If length of duct exceeds 20 mts the lumination or lux level of light should be high.
After installation / erection of ducts and before insulating of ducts this test should be carried out else it ll be difficult to identify the pin holes.
select the duct to be test and select the light, place the light in side of duct and ensure there ll be no flamable items remains inside, close the both ends with end cap and switch on the light, the leakage ll be identify by you with the help of light rays.if the leackage is minor ( pin hole ) apply the silicon sealent, if it major uninstall the duct and rectify.
