Case study · Healthcare
Duct cleaning and sanitisation of the negative-pressure isolation rooms at Hospital Shah Alam — NICU, ICU, CCU, HDW and seven wards — completed room by room inside the hospital’s shutdown schedule.
The brief
Negative-pressure isolation rooms protect patients and staff by drawing air inward and exhausting it through HEPA filters. Over time, the supply ducts, plenums and exhaust risers serving these rooms collect dust and biological growth. The work had to be done room by room, as each ward released its rooms, and handed back clean, sealed and ready for new filters.
Objectives
Remove dust, debris and biological growth from both the supply and exhaust sides.
Sanitise rooms and treat ducts with anti-microbial products that resist regrowth of bacteria, fungi and mould.
Leave exhaust housings clean, dry and re-sealed for new HEPA filters so negative pressure can be restored.
Record conditions before and after, and report defects found above the ceiling.
Complete every room within its ward shutdown window.
Method
Only existing openings were used — diffusers, louvres, access panels and the HEPA hatch. Each room was terminal-sanitised by ULV fogging with an anti-microbial surface treatment before the supply and exhaust sides were cleaned and treated with an anti-microbial duct treatment.
Timeline
| Week | Date | Rooms | Notes |
|---|---|---|---|
| Week 1 | 21–23 Sep | 5 | Mobilisation; Day 1 in ICU |
| Week 2 | 28 Sep | 4 | Two teams working in parallel |
| Week 3 | 5 Oct | 4 | Heaviest fouling found and reported |
| Week 4 | 12 Oct | 4 | Robot entry from an adjacent room where access was blocked |
| Week 5 | 19 Oct | 4 | Final room handed over the same evening |
Rooms cleaned
Findings
Cleaning is also an inspection. Defects outside our scope were recorded with photos and reported to the facility team.
In one O&G ward room we found biofilm on the FCU drain pan and casing, and condensation with black staining on a main duct with no access opening. We recommended checking insulation and condensate drainage and adding an access opening.
Water dripping in an orthopaedic room was flagged with possible sources so it could be traced before the ceiling was closed.
Where formwork blocked an FCU ceiling opening, the team crossed from an adjacent room and the robot entered from the other side — no formwork was cut.
An exhaust filter housing located outside its room was reached and cleaned, with robot video recorded for the file.
Recommendations
Our report closed with a practical maintenance plan aligned to ASHRAE 170 and 180, NADCA ACR 2021 and the DOSH ICOP-IAQ.
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