1.4 - SURVEYING - CHLORIDE TESTING - FIRE MODULE

Question 1

What are the use of chloride testing & it’s benefits?

Answer 1

1USE: Tests can reveal levels of chlorides produced following a fire.
2. BENEFIT: Knowledge provide can be used to evaluate the likelihood of corrosive damage from fire residues

Question 2

What are the potential sources of chlorides?

Answer 2

1. PVC (poly vinyl chloride) - plastic drainage pipework is commonly made of PVC.
   - when this burns hydrogen chloride is formed which combines with water to form hydrochloric acid = strong, damaging acid.

Question 3

What are the limitations of the testing method?

Answer 3

1. Some methods are not specific for chlorides and given an indication of presence of other halogens inc chloride
2. Some methods have a v restricted range over which they work

Question 4

Does chloride testing need to be carried out in different areas of fire damaged property?

Answer 4

1. Yes, repeat testing required in diff areas as chloride levels are not consistent
2. Look for visible corrosion to support test results
3. Should be tested by competent person.

Question 5

What are factors affecting acid damage?

Answer 5

1. Higher contaminations of acid in the fire residues, it is possible to measure the concentration.
2. Time - increases w time
3. Higher relative humidity (RH) - corrosion needs moisture and is slowed at lower levels. Slowed below 60%,very slow below 50%, even slower below 40% RH.

Question 6

If RH is below 30% what’s the risk?

Answer 6

Risk of electrostatic changes being generated which can cause damage to electronics