Softwall and portable cleanroom booths: fit and realistic class

By ZY Cleanroom · Updated 2026-11-01 · Sources at the end of the page

When a booth fits

Check the rule before the product. The table lists four cases. FDA names carefully designed curtains as barriers that can segregate an aseptic line in suitable places. It does not name them as room walls.

What class you can claim

A class is a particle count. ISO 14644-1 sets the limits and names no wall type. We found no standard or independent test data that assigns a class to softwall booths. Treat any class claim as unproven until it is counted.

The table shows the 0.5 µm limits and the air supply references. The USP <797> air changes apply to compounding rooms. They are not a rule for every booth. They show the scale of supply a classed room needs.

Worked example: air supply for one booth

Assumed booth of 3 × 3 × 2.4 m is 21.6 m³. At 30 air changes per hour the supply is 21.6 × 30 = 648 m³/h. At 20 it is 432 m³/h. A fan filter unit that supplies an assumed 1,000 m³/h gives 1,000 ÷ 21.6 = 46 air changes per hour in the same booth, before any leakage.

Leakage and entry decide the result

Curtain gaps, an open skirt and door openings let outside air in. Annex 1 gives a minimum 10 Pa difference between adjacent rooms of different grade as a guidance value (para 4.14). Test whether the booth holds a pressure with the door closed and during entry.

FDA asks for airlocks between the entrance to an aseptic manufacturing area and the adjoining unclassified area. A booth entered straight from open floor has no such buffer. Ask how entry is handled.

Annex 1 para 4.32 sets requalification at no more than 6 months for grade A and B and 12 months for grade C and D. Ask which tests repeat after the booth is moved.

Curtain materials and fire

If the curtain material is thinner than 6 mm, ANSI/FM 4910-2013 sends it to the parallel panel test. It sets flame height at 1.83 m or less among five conditions. Ask for the test report of the curtain material. A material test does not approve the booth.

Put these in the data sheet

State the class and the room state, at rest or in operation. State the particle sizes to count, the count positions, the air supply and its velocity, the pressure target, the entry method, the curtain fire test and the retest after a move.

Who approves the room

Your regulator or customer auditor judges the facility. The supplier builds to your data sheet and supplies test results. The owner keeps the responsibility. To have a room list reviewed, send it to ZY Cleanroom, a cleanroom design-and-build contractor with its own panel factory in Tianjin, China.

Shipping container clean room: size, volume and what the box does not decide

A shipping container cleanroom is a standard steel container lined with panels and fitted with an air system. Start from the carrier's published inside sizes, because the lining and floor build-up take space. The table follows Maersk's equipment specification for its dry containers (undated; checked 1 November 2026). Sizes vary by container series, so confirm the unit you buy.

Assumed values: a 50 mm lining on the walls, floor and ceiling of a 20 ft standard container leaves 5.796 × 2.250 × 2.293 m, which is 29.9 m³. That is about 9% less than the carrier's 33 m³. At the 30 total air changes per hour that the USP <797> row in the table above lists for ISO 7 compounding rooms, the supply is 29.9 × 30 = 897 m³/h, or 598 m³/h at 20. An airlock, equipment and returns take more of this space.

The box does not decide the class. A panel-lined container has fixed walls, the point the table above raises against curtain booths, but the finished room must still meet the surface and sealing rules (EU GMP Annex 1 paras 4.5, 4.6 and 4.8) and show its class by particle count under ISO 14644-1. The door opening limits the largest item you can bring in after lining, so list large equipment first.

Related guides

• What a cleanroom costs to run: energy, filters and testing
• How to audit a cleanroom panel factory, on site or by video
• How long does it take to build a cleanroom?
• Cleanroom cost per m²: published ranges by ISO class
• Turnkey cleanroom contractor
• Room list builder

Sources

• Washington State Department of Health, Pharmacy Self-Inspection Worksheet, 2026 USP 797 Sterile Compounding Addendum, DOH 690-296 (January 2026), which reproduces USP <797> text by section; checked 1 November 2026
• ISO 14644-1:2015, Cleanrooms and associated controlled environments, Part 1: Classification of air cleanliness by particle concentration, Table 1 (preview copy on iTeh Standards; checked 1 November 2026)
• EudraLex Volume 4, Annex 1: Manufacture of Sterile Medicinal Products (published 25 August 2022, applied from 25 August 2023; checked 1 November 2026)
• FDA, Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing, Current Good Manufacturing Practice (September 2004, nonbinding; checked 1 November 2026)
• FM Approvals, ANSI/FM 4910-2013 (2021), American National Standard for Cleanroom Materials Flammability Test Protocol, sections 2.2, 2.4, 2.5 and 6 (reaffirmed 29 November 2021; checked 1 November 2026)