A cleanroom two-piece suit (a top plus trousers, two pieces) and a coverall (top and bottom joined as one piece) differ in coverage and where the joins are: a coverall covers the whole body in one piece and closes with a zipper at the front; a two-piece suit relies on the top and trousers overlapping. EU GMP Annex 1 says that for Grade C areas either a single or two-piece trouser suit is acceptable, so both styles have a regulatory basis; which one to pick follows the plant’s cleanliness grade and operating procedures (SOP).
Sources: EU GMP Annex 1 (2022 edition), clause 7.13 (Grade C: a single or two-piece trouser suit gathered at the wrists and with high neck); Ansell, “The Ansell Guide To Cleanroom Apparel” (a coverall should provide full-body coverage, with a closed zipper at the front and elastic cuffs and ankles); Ansell, “EU GMP Annex 1: Are You Dressed For The Part?”.
This article is divided into 4 comparison points: ① what each style is ② what the regulations say ③ seams and fit ④ how to choose. This is the general case; in practice, your plant’s cleanroom rules govern.
Point ①: What each style is
| Item | Coverall | Two-piece suit |
|---|---|---|
| Construction | Top and trousers joined as one piece | Long-sleeve lapel-collar top plus trousers, two pieces in all |
| English term | coverall | two-piece suit (EU GMP Annex 1 writes two-piece trouser suit) |
| Between top and trousers | No overlap (top and bottom are one piece) | There is an overlap (top and trousers lap over each other) |
| Styles on Jiahon’s site | Hooded coverall (front opening, no-mask style): adjustable hook-and-loop at the back of the hood, elastic waist, double-slot pen pocket on the arm | Two-piece suit: long-sleeve lapel-collar top plus trousers |
| Pattern | Stripe, grid | Stripe |
| Minimum order | 10 pieces minimum, sizes can be mixed | Please inquire |
| Fabric | Polyester filament with embedded conductive fiber, grid weave | Polyester filament with embedded conductive fiber, grid weave |
Sources: the English terms and the coverall’s zipper, cuffs and ankles are taken from Ansell, “The Ansell Guide To Cleanroom Apparel” and EU GMP Annex 1 (2022 edition), clause 7.13; Jiahon’s styles, patterns, minimum orders and fabric are taken from Jiahon’s “Cleanroom Garment Series” product page.
Point ②: What the regulations say
EU GMP Annex 1 (2022 edition), clause 7.13, words personnel clothing for Grade C areas as follows: hair, beards and moustaches should be covered, and a single or two-piece trouser suit is worn, gathered at the wrists and with a high neck. In other words, at the Grade C level, both coveralls and two-piece suits comply with the clause. The clause for Grade B areas (including work entering Grade A) refers to sterile headgear, sterile garments, and clothing specifically for wearing under the sterile garments; the clause we read does not specify single or two-piece.
Annex 1 is a clause of the EU GMP for medicinal products. Electronics plants and semiconductor fabs should follow their own cleanroom rules and audit requirements; it is placed here to show how a regulation divides the grades. Another example comes from a CSE article: ISO 3 work calls for a coverall covering the whole body, with multiple layers on some parts; for ISO 8, the suggested combination is a bouffant cap, face mask, frock, gloves and shoe covers. From these two examples a trend can be read: the higher the cleanliness requirement, the more the tendency toward full-body coverage. This is a trend read from examples, not a clause.
Sources: EU GMP Annex 1 (2022 edition), clause 7.13 (7.13 ii, Grade C); Ansell, “EU GMP Annex 1: Are You Dressed For The Part?” (restating the Grade C clause of Annex 1); CSE, “Protective cleanroom clothing essentials” (clothing suggestions for ISO 3 and ISO 8).
Point ③: Seams and fit
The Ansell guide requires that seams on cleanroom garments be bound seams, so that air and particles cannot pass through gaps; a coverall should have a closed front zipper and elastic cuffs and ankles. The CSE article cautions: garments that are too large, or several garments that do not fit well together, leave gaps that let particles from skin or hair escape. In other words, whichever style you choose, these are the positions to check:
| Check position | Coverall | Two-piece suit |
|---|---|---|
| Collar and front opening | Is the zipper closed, does the collar sit close to the neck | Do the top’s front opening and collar sit close to the neck |
| Cuffs | Are the cuffs elastic | Same as left |
| Ankles / trouser hems | Are the ankles elastic | Are the trouser hems gathered |
| Between top and trousers | This position does not exist | When moving, does the overlap expose skin or inner clothing |
Sources: Ansell, “The Ansell Guide To Cleanroom Apparel” (bound seams, the coverall’s front zipper and elastic cuffs and ankles); CSE, “Protective cleanroom clothing essentials” (oversized or poorly matched garments leave gaps).
As for which of the two styles sheds fewer particles: the regulations and supplier materials cited in this article all specify the whole garment set by cleanliness grade, and do not set particle-shedding figures for coveralls and two-piece suits side by side, so this article does not say which one sheds less. To compare, please use your plant’s own measurements, or the test report for the style.
Point ④: How to choose
The Ansell guide puts it plainly: for what clothing to wear, look at that cleanroom’s standard operating procedure (SOP). So to choose a style, first confirm what your plant’s SOP and cleanliness grade specify; where the SOP does not specify, use the four questions below to narrow it down.
| Question | How to look at it | Match |
|---|---|---|
| Do the SOP and cleanliness grade specify a coverall, or allow two-piece? | The SOP governs | Coverall specified: choose the hooded coverall; two-piece allowed: both can be compared |
| Does the work need full-body coverage, or is upper body plus trousers enough? | Look at the work and the SOP | Full-body coverage: hooded coverall; otherwise: two-piece suit |
| Does static control call for a grid pattern? | Grid spacing per your plant’s electrostatic discharge (ESD) control rules | Grid-pattern styles on Jiahon’s site are the jacket, the long coat and the hooded coverall; the two-piece suit is striped |
| How to arrange quantity and sizes? | The number of pieces in one order and the size split | Hooded coverall 10 pieces minimum, sizes can be mixed; for the two-piece suit minimum order, please inquire |
Sources: Ansell, “The Ansell Guide To Cleanroom Apparel” (look at the clothing the SOP specifies); Jiahon’s “Cleanroom Garment Series” product page (styles, patterns, minimum orders and the three selection questions).
In SMT/EMS and packaging plants: cleanroom garments must also control static
In electronics plants, cleanroom garments are also ESD protection. The EU GMP Annex 1 cited in this article is a pharmaceutical regulation; electronics and packaging plants, besides cleanliness, must also control charge on the human body. One packaging plant’s ESD control specification in the engineering materials states: the potential generated by wearing cleanroom garments must not exceed 200 V, and ESD shoes and wrist straps are measured daily. So beyond choosing two-piece or coverall, the fabric should have conductive yarn, the cuffs and trouser hems should be groundable (wrist straps, shoes), and the whole set should be brought into an ANSI/ESD S20.20 control program.
SMT lines do not necessarily need full coveralls. SMT printing, placement and reflow mostly take place in workshops of ordinary cleanliness grade, where ESD two-piece suits or ESD smocks plus caps and shoes are commonly worn; it is areas such as wafer-level packaging, flip chip and optical modules that require higher-grade coveralls and hoods. For how the grades are set, see the article on cleanroom classes (ISO 14644-1).
The garments themselves also need verifying. For cleanroom garment laundering, service life and particle-shedding tests, the industry often refers to IEST-RP-CC003 (recommended practice for cleanroom garment systems); audits often ask “how many times has it been washed, and how often is it replaced”. One audit checklist from an outsourced packaging and test house also lists “environment (cleanroom, ESD)” as one of 7 areas.
Frequently asked questions
Two-piece suit or coverall: which one sheds fewer particles?
The regulations and supplier materials found so far do not set particle-shedding figures for the two styles side by side, so it cannot be said which one sheds less. The regulatory approach is to specify the whole garment set by cleanliness grade; to compare, please use your plant’s own measurements or the test report for the style.
Sources: EU GMP Annex 1 (2022 edition), clause 7.13; Ansell, “The Ansell Guide To Cleanroom Apparel”.
Must a coverall always be worn in a cleanroom?
Not necessarily. EU GMP Annex 1 says that for Grade C areas either a single or two-piece trouser suit is acceptable, gathered at the wrists and with a high neck. What to wear in practice follows your plant’s SOP and audit requirements.
Sources: EU GMP Annex 1 (2022 edition), clause 7.13 (7.13 ii); Ansell, “EU GMP Annex 1: Are You Dressed For The Part?”.
What details should you check on a coverall?
Check whether the front zipper is closed, whether the cuffs and ankles are elastic, whether the seams are bound seams, and whether the size fits. Too large, or poorly matched, leaves gaps that let particles escape.
Sources: Ansell, “The Ansell Guide To Cleanroom Apparel”; CSE, “Protective cleanroom clothing essentials”.
How do Jiahon’s two-piece suit and hooded coverall differ?
Both are cleanroom garments of polyester filament with embedded conductive fiber. The hooded coverall is a front-opening, no-mask style, comes in stripe and grid, with a 10-piece minimum order and sizes that can be mixed; the two-piece suit is a long-sleeve lapel-collar top plus trousers, striped, and for its minimum order please inquire. The 2019 test report attached to the product page covers fabric samples, not whole finished garments, and does not include particle shedding or cleanliness grade.
Source: Jiahon’s “Cleanroom Garment Series” product page.
Further reading and related products
For styles, sizes and quotes, see Cleanroom Garment Series. For how to put the whole outfit together, see “How to Choose Cleanroom Wearables” and “How to Choose Cleanroom Garments, Cleanroom Shoes and ESD Slippers“; for how cleanliness grades compare, see “Cleanroom Class Comparison“. For matching head and foot items, see Cleanroom Caps and Bouffant Caps Series and Cleanroom Shoe Covers Series. Single-use protective clothing is not a launderable cleanroom garment; see Disposable Protective Coveralls.
Have a similar question? Write to Jiahon and see whether there is a matching solution.
Notes: scope and exceptions
This article covers how to compare and choose between two-piece suits and coveralls among launderable cleanroom garments; it does not include selection of single-use protective clothing, gloves or shoe covers. EU GMP Annex 1 is a regulation for medicinal products and sterile preparations; electronics plants should follow their own rules. This is the general case and still depends on the individual case.