{"id":783,"date":"2026-05-20T09:54:08","date_gmt":"2026-05-20T09:54:08","guid":{"rendered":"https:\/\/www.hongjieseal.com\/?p=783"},"modified":"2026-05-21T09:59:01","modified_gmt":"2026-05-21T09:59:01","slug":"fda-wras-certified-rubber-seals-buyer-guide","status":"publish","type":"post","link":"https:\/\/www.hongjieseal.com\/fr\/fda-wras-certified-rubber-seals-buyer-guide\/","title":{"rendered":"FDA and WRAS Certified Rubber Seals: What Drinking Water and Food Equipment Buyers Need to Know"},"content":{"rendered":"<\/p>\n

FDA and WRAS certified rubber seals are compounds tested and approved for direct contact with food or potable water \u2014 FDA 21 CFR 177.2600 governs food contact in the United States, while WRAS BS 6920 covers materials touching drinking water in the UK. They are not interchangeable<\/strong>: a seal can be FDA compliant and still fail WRAS, and vice versa. If your product touches both food and water, or ships to multiple markets, you usually need both certifications on the same compound \u2014 and that has real implications for material choice, cost, and lead time.<\/p>\n

FDA vs WRAS: Two Standards, Two Very Different Tests<\/h2>\n

Buyers often assume \u201cfood grade\u201d and \u201cwater grade\u201d mean the same thing. They don’t.<\/p>\n

FDA 21 CFR 177.2600<\/strong> is a list-based standard. It tells the rubber compounder which ingredients (polymers, fillers, plasticizers, curing agents) are permitted in materials intended for repeated food contact. The finished compound is then tested for extractables in water and hexane simulants. Pass those limits and you can claim FDA compliance.<\/p>\n

WRAS BS 6920<\/strong> goes further. It tests how the rubber behaves in actual potable water over time \u2014 specifically whether the seal affects taste, odor, appearance, encourages microbial growth, or leaches metals and cytotoxic substances. A compound has to pass all five sub-tests, and the approval is granted to a specific manufacturer using a specific recipe and process. Change the supplier of carbon black? You may need to re-test.<\/p>\n

That is why a single batch of EPDM can be FDA compliant out of the box but require six to nine months of reformulation and testing to achieve WRAS approval. The implication for buyers: ask for both certificate numbers, not just a verbal claim.<\/p>\n

\"EPDM
EPDM O-rings tested for WRAS BS 6920 drinking water compliance<\/figcaption><\/figure>\n

Which Rubber Materials Actually Pass Both Standards<\/h2>\n

Not every elastomer plays well with water and food. The shortlist is narrower than most buyers expect.<\/p>\n

EPDM (peroxide-cured)<\/h3>\n

The workhorse for drinking water. Excellent resistance to hot water, chlorinated water, and ozone. Peroxide-cured grades \u2014 not sulfur-cured \u2014 are the ones that typically pass WRAS, KTW, and NSF 61. Temperature range roughly -40\u00b0C to +150\u00b0C.<\/p>\n

Silicone (VMQ)<\/h3>\n

The default for food equipment where you need wide temperature range (-60\u00b0C to +200\u00b0C) and flexibility. Common in coffee machines, dairy equipment, and baby-bottle seals. Platinum-cured silicone is preferred over peroxide-cured for food contact because it leaves no by-products.<\/p>\n

NBR (food grade)<\/h3>\n

Used where the seal contacts fatty or oily foods \u2014 vegetable oil pumps, dispensers, meat-processing gaskets. White or cream-colored NBR is common to make contamination visually obvious. Avoid for drinking water; it can affect taste.<\/p>\n

FKM \/ Viton<\/h3>\n

For aggressive food processing (citric acid, CIP cleaning chemicals, steam) or hot oils. FDA-compliant grades exist; WRAS-approved FKM is rarer and expensive.<\/p>\n

Our engineering team<\/a> typically recommends peroxide-cured EPDM as the starting point for any project that mixes hot water, cold water, and occasional steam cleaning \u2014 it covers the broadest application range with a single compound.<\/p>\n

\"Food-grade
Food-grade silicone and EPDM rubber seals in multiple colors<\/figcaption><\/figure>\n

Common Sourcing Mistakes (and How to Avoid Them)<\/h2>\n

Three mistakes account for most failed audits we see.<\/p>\n

1. Trusting a generic \u201cfood grade\u201d data sheet<\/h3>\n

\u201cFood grade\u201d alone means nothing. Always ask for the specific certificate: FDA letter from the compounder, WRAS approval number searchable on the WRAS website, or NSF listing ID. A legitimate supplier will send these without hesitation.<\/p>\n

2. Assuming color equals compliance<\/h3>\n

Blue rubber is popular in food plants because metal detectors and visual inspection catch fragments easily \u2014 but the color itself doesn’t make a compound food safe. The pigment must also be FDA-listed. We have seen factories use generic blue masterbatch in \u201cfood grade\u201d gaskets, which technically voids compliance.<\/p>\n

3. Mixing compliant and non-compliant parts in one assembly<\/h3>\n

If a valve has one WRAS gasket and one standard NBR O-ring on the same water path, the whole assembly fails. Audit every elastomer in the wetted flow path, including small backup seals and dust caps.<\/p>\n

For example, a UK kitchen-tap manufacturer once sourced WRAS EPDM main seals from us but kept using an existing supplier’s unmarked NBR O-rings on the cartridge. Their first regulatory audit caught it. Replacing the small NBR rings with matching WRAS EPDM added about 3 cents per unit \u2014 far cheaper than a recall.<\/p>\n

Temperature, Pressure, and Cleaning: The Hidden Variables<\/h2>\n

A certificate proves a compound is safe at the test conditions. Real applications often exceed them, and that is where field failures start.<\/p>\n

Standard WRAS testing runs at three temperatures: cold (up to 25\u00b0C), warm (up to 65\u00b0C), and hot (up to 85\u00b0C). If your espresso boiler runs at 120\u00b0C and 12 bar, you need a compound approved at the hot rating and<\/em> validated for your pressure cycle. Ask for the temperature class on the WRAS certificate \u2014 it is the single most overlooked detail in spec sheets.<\/p>\n

Cleaning chemistry matters just as much. CIP (clean-in-place) cycles in dairy and brewing equipment use 2-3% caustic at 80\u00b0C followed by nitric acid rinse. EPDM handles this well. Silicone tolerates it but swells slightly. NBR degrades quickly. If your customer runs aggressive CIP, choose peroxide-cured EPDM even if the food product itself looks gentle.<\/p>\n

\"Stainless
Stainless steel food processing pipeline with rubber gasket joints<\/figcaption><\/figure>\n

Standards Comparison Table<\/h2>\n

Quick reference for the four certifications that come up most often in B2B sourcing conversations:<\/p>\n

See the comparison table above for region, scope, testing focus, typical materials, and renewal requirements. A few practical notes:<\/p>\n