Identify where the moisture appears
Condensation inside a duct and moisture on its outer surface are different observations. Vapour in the exhaust can condense as conditions change along the route. A cold outer surface can also collect moisture from surrounding air.
Record the location without opening or disturbing chemical-exhaust equipment. Visible liquid can have other causes, including leaks or weather entry, so the investigation should establish the source.
Prepare an observation record
| Observation | Record safely |
|---|---|
| Position | Inside or outside, joint or straight section, indoor or rooftop route. |
| Timing | During operation, after shutdown or following weather changes. |
| Process | Substances, moisture and heat associated with the task. |
| Condition | Staining, deposits, damage or changes noticed nearby. |
Follow the laboratory’s procedure for unidentified or potentially contaminated liquid. Keep people clear of an affected area when required by that procedure.
Review the route and operating conditions
The designer may need to consider the exhaust composition, temperatures, route, operating pattern and material compatibility. Drainage, insulation or other changes require an application-specific assessment.
Our ducting guide helps gather material information. The fitting schedule helps describe the affected section if a replacement or route change is being considered.
Keep changes documented
Agree the scope before modifying a duct or adding a drain. Include how residues will be managed, who can access the system and what checks are needed before it returns to use.
- Keep photographs and observations with the service record.
- Record the confirmed cause and agreed repair.
- Update drawings when the route or components change.
- Review whether operating instructions need updating.
For a wider equipment review, use the maintenance checklist to coordinate the cupboard, fan and ducting.