Hospital Corridor Finish Inspection
A 2,000 m2 VCT corridor in a hospital is cleaned nightly with a 500-rpm auto-scrubber and a neutral cleaner at 1:128, then burnished with a 1,500-rpm propane burnisher and a UHS pad. The finish is 6 weeks old and has 5 coats. Under a low-angle inspection light at 300 lux, with the viewer 1.5 m from the wall, the charge nurse reports a swirl pattern in the traffic lanes and a white powder along the edges. The floor feels slightly tacky near the entrance. The burnisher pad was last changed 10 days ago and is dark gray. The auto-scrubber squeegee leaves a 25 mm strip of water at the end of each pass. The building uses 18 C water, and the cleaner is mixed in a 20 L bucket by a 30 mL pump.
1. Design an inspection procedure to determine whether the white powder and swirl marks are surface residue, finish damage, or both. Include what to inspect and how to interpret test areas.
Read the worked answer
Inspect under low-angle light at the same 300 lux, from several angles, comparing traffic lanes, edges, and a known-good area. Record the pattern: powder along edges often points to burnisher dust or cleaner residue; swirls in lanes suggest a pad or machine pattern. Wipe a 0.5 m2 area with a white cloth and neutral cleaner at the correct dilution, then rinse and dry. If the cloth picks up white material and the gloss returns, the powder is residue. If the swirl remains after cleaning, it is in the finish. Test a small area with a clean UHS pad or a finish restorer; if the swirl fades, it is surface burnishing. If it remains, the finish is worn or heat-damaged. Check the tacky entrance separately: clean, rinse, and dry a 1 m2 patch; if tackiness persists, suspect overapplication, poor rinsing, or incompatibility. Compare sheen with a gloss meter if one is available.
2. Recommend corrections to the cleaning and burnishing program, and state whether recoating is needed now.
Read the worked answer
Correct the mechanical issues first: replace the dark gray pad, clean or change pads daily, and reduce burnisher passes. A dirty pad can leave swirls and powder. Fix the auto-scrubber squeegee so it leaves no water strip; a 25 mm strip means the blade is worn, misadjusted, or the machine is moving too fast. Verify the 1:128 dilution with the 30 mL pump and a measured 20 L bucket; a worn pump can over- or under-dose. Rinse the tacky entrance with clean water and dry it.
If inspection shows only surface residue and the swirl buffs out, no recoat is needed; burnish with a clean pad after cleaning. If the finish is worn in the lanes or the swirl is heat damage, clean, rinse, and apply one or two coats to the traffic lanes, then allow proper cure before burnishing. Do not burnish a tacky floor.