Initial DIY Cleanroom Experimentation

Jeff Kaufman documents hands-on tests of a DIY cleanroom concept: using a powerful HEPA air purifier (AirFanta 3Pro) to positively pressurize a single room as an improvised bioshelter. He explains why whole-house pressurization feels risky and instead tries simpler experiments to see what a household purifier can achieve. Initial sealed testing with a trash bag taped over the unit produced an 83 Pa pressure reading. Practical room setups exposed major challenges: axial fans can stall under pressure, consumer units use friction-fit assemblies that fail under side loading, and ordinary homes leak a lot. The AirFanta is close to a best-case consumer option, but most people will not have an equally capable purifier.

Practical room tests used a Testo 510i manometer (5 Pa-rated) and produced a repeat 12 Pa differential when the unit was mounted through a 13x13" wall hole, after jury-rigging the unit with baling wire and tape to stop leaks. Kaufman plans finer sensing with an SDP810-500PA sensor wired to an Arduino and a PMS5003 particle monitor to correlate pressure with particle counts. He notes required pressure depends on leak paths (direct-to-outside vs. into wall cavities), tried crude smoke tests and PM2.5 measurements, and suggests winter reverse-pressure checks, thermal imaging, or simple tactile tests to find leaks. The hole will be restored for future emergency use while further measurements continue.