Deep dive · parts

Lids, seals and the compatibility table you should bookmark

Elastomer choice is the most common quiet mistake in bulk liquid handling. Pick the wrong seal and the container does not fail on day one — it fails on day forty, overnight, onto concrete.

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Get the right elastomer first time

Name the product and the temperature. We will specify the seal rather than let you guess.

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Short answer

EPDM is the right default: water, dilute acids and alkalis, glycols, most food products, outdoor weathering. Viton (FKM) for aromatics, chlorinated solvents, fuels, oils, fats and higher temperatures. Silicone for high-temperature food transfer but never for oils. PTFE when nothing else is chemically acceptable, accepting that it needs a flat, well-maintained sealing face. Replace at every valve removal and every product change.

Elastomer compatibility for IBC outlet gaskets and lid seals
Product	EPDM	Viton (FKM)	Silicone	PTFE	Recommended
Water, potable & process	Excellent	Excellent	Excellent	Excellent	EPDM
Dilute acids (<10%)	Good	Excellent	Fair	Excellent	EPDM
Concentrated acids	Poor	Good	Poor	Excellent	PTFE
Caustic soda, alkalis	Excellent	Fair	Fair	Excellent	EPDM
Liquid fertiliser, UAN	Excellent	Good	Fair	Excellent	EPDM
Glycols, coolants, de-icer	Excellent	Good	Good	Excellent	EPDM
Surfactants, detergents	Excellent	Good	Good	Excellent	EPDM
Edible oils, fats	Poor	Excellent	Poor	Excellent	Viton
Aromatic solvents	Poor	Excellent	Poor	Excellent	Viton
Chlorinated solvents	Poor	Good	Poor	Excellent	Viton / PTFE
Alcohols	Good	Good	Good	Excellent	EPDM
Fuels, diesel, kerosene	Poor	Excellent	Poor	Excellent	Viton
Juice & syrup concentrate	Excellent	Excellent	Excellent	Excellent	FDA EPDM
Brine, pickling liquor	Good	Excellent	Fair	Excellent	Viton
Hot fill 140–180°F	Fair	Excellent	Excellent	Excellent	Viton / silicone
Hydrogen peroxide (dilute)	Good	Fair	Fair	Excellent	EPDM / PTFE

General guidance for ambient service unless stated. Concentration, temperature and exposure time all shift these ratings; for anything marginal, send us the product and we will check it against the manufacturer's data rather than a generic chart.

Lids: vented or solid

The 6-inch screw lid is the standard top closure on composite IBCs. The choice that matters is venting.

Vented. A one-way or two-way vent lets air in as liquid is drawn out and lets pressure out as a product off-gasses or warms. Essential for anything fermenting, for pumped discharge, and for outdoor storage where day–night temperature swings breathe the container.
Solid. Fully sealed. Correct for transport, for products that must not exchange air, and wherever the closure forms part of an authorised packaging under DOT rules.

The failure mode of getting this wrong is memorable: a solid lid plus a transfer pump draws the bottle inwards until a wall panel buckles permanently. We see several of those a year, and the container is rarely recoverable beyond Grade C.

Seals and caps

Every lid we fit gets a new seal — foam for benign duty, EPDM or silicone for food, Viton for aggressive chemistry. Outlets get a tamper-evident dust cap, which is both transit protection and a visible sign that nobody has opened the valve since loading.

Diagnosing a seal failure in the field

Hardened and shiny: heat-aged or ozone-attacked. Replace; consider shading the container.
Swollen and soft: chemically attacked. Replace with a different elastomer — the material was wrong, not the part.
Permanently flattened: compression set from being over-torqued or left under load for years. Normal wear; replace routinely.
Cracked at the inner edge: usually mechanical, from a valve being cross-threaded on. Check the boss thread before refitting.
Clean and sound but still weeping: the sealing face is the problem, not the gasket. Inspect the boss for scoring, and the valve flange for warp.

If a new gasket, a new valve and a clean boss do not stop it, the bottle is the issue and the decision becomes rebottle or recycle.

Questions

Lid & gasket FAQ

How often should an IBC gasket be replaced?

Every time the valve comes off, and at every change of product. A gasket is a few dollars; a compression-set gasket that weeps 40 gallons of fertiliser onto a yard is not. For containers in continuous service, replace annually as routine maintenance even if nothing appears wrong.

Should I use a vented or solid lid?

Vented for anything that off-gasses, ferments, or is drawn down by a pump — without venting you will collapse the bottle inwards. Solid for transport of a product that must stay sealed, and for anything shipped under DOT regulation where the closure is part of the authorised packaging. If in doubt on a static storage tank, vented.

Why did my gasket swell up?

Chemical attack. The classic case is EPDM exposed to aromatic or chlorinated solvents, fuels or fats: it absorbs, swells, loses its set and then will not seal again even after drying. Switch to Viton for that service. A gasket that has hardened and cracked instead has usually been heat-aged or ozone-attacked.

Are your gaskets food-safe?

We stock FDA-compliant EPDM, silicone and Viton grades alongside the industrial ones, and food-grade units are always built with the compliant versions plus a new lid seal. Ask for the compliance reference and it ships with the order.

Keep reading

Valves & fittings

Identify your thread.

Keep reading

Pallets & cages

The structural half.

Keep reading

Food-grade totes

Where FDA elastomers matter.

Compatibility data, in full

Twenty-one media, four elastomers, one hundred prior products

Elastomer choice is the most common quiet mistake in bulk liquid handling. Here is every pairing we hold data on.

71%of reported leaks are the outlet gasket412 logged reports

14%are valve seat wear≈ $38 to fix

9%are the lid seal≈ $11 to fix

6%are an actual bottle failurerebottle or replace

21media in the compatibility matrixEPDM, Viton, silicone, PTFE

Every changeof product is a gasket changeand every valve removal

Elastomer compatibility for outlet gaskets and lid seals — 21 media
Medium	EPDM	Viton (FKM)	Silicone	PTFE	We would fit
Water, potable & process	Excellent	Excellent	Excellent	Excellent	EPDM
Dilute acids (<10%)	Good	Excellent	Fair	Excellent	EPDM
Concentrated acids	Poor	Good	Poor	Excellent	PTFE
Caustic soda, alkalis	Excellent	Fair	Fair	Excellent	EPDM
Liquid fertiliser, UAN	Excellent	Good	Fair	Excellent	EPDM
Glycols, coolants, de-icer	Excellent	Good	Good	Excellent	EPDM
Surfactants, detergents	Excellent	Good	Good	Excellent	EPDM
Edible oils, fats	Poor	Excellent	Poor	Excellent	Viton
Mineral oils	Poor	Excellent	Poor	Excellent	Viton
Aromatic solvents	Poor	Excellent	Poor	Excellent	Viton
Chlorinated solvents	Poor	Good	Poor	Excellent	Viton / PTFE
Ketones (acetone, MEK)	Fair	Poor	Poor	Excellent	PTFE
Alcohols	Good	Good	Good	Excellent	EPDM
Fuels, diesel, kerosene	Poor	Excellent	Poor	Excellent	Viton
Juice & syrup concentrate	Excellent	Excellent	Excellent	Excellent	FDA EPDM
Brine, pickling liquor	Good	Excellent	Fair	Excellent	Viton
Hot fill 140–180°F	Fair	Excellent	Excellent	Excellent	Viton / silicone
Hydrogen peroxide (dilute)	Good	Fair	Fair	Excellent	EPDM / PTFE
Sodium hypochlorite	Good	Good	Fair	Excellent	EPDM
Steam / CIP chemistry	Excellent	Fair	Good	Excellent	EPDM
Outdoor weathering & ozone	Excellent	Good	Excellent	Excellent	EPDM

Seals — 4 line items, all stocked or built in York
Part	Group	Options	Materials	Typical use	Availability
Outlet gasket, flat	Seals	EPDM, Viton, silicone	FDA grades available	The usual cause of a leak	Stocked
Outlet gasket, O-ring	Seals	EPDM, Viton	FDA grades available	Some valve patterns	Stocked
PTFE envelope gasket	Seals	EPDM or silicone core	PTFE	Aggressive or mixed chemistry	1–3 days
Lid seal	Seals	Foam, EPDM, silicone	FDA grades available	Second most degraded part	Stocked

Closures — 4 line items, all stocked or built in York
Part	Group	Options	Materials	Typical use	Availability
6" screw lid, vented	Closures	One-way, two-way vent	HDPE	Pumped discharge, off-gassing, outdoor	Stocked
6" screw lid, solid	Closures	—	HDPE	Sealed transport, DOT closures	Stocked
Tamper-evident dust cap	Closures	Plain, numbered	PE	Transit protection and evidence	Stocked
Camlock dust plug / cap	Closures	DC, DP	PP, aluminium	Closing an unused half	Stocked

Per product

Which seal each prior product needs

The same list our fit-out station works from — one hundred named products with the elastomer we would fit.

Our internal prior-product list, published — 110 named products
Prior product	Family	SG	Programme	Best grade	Food?	Seal	What to watch
Apple juice concentrate (70 Bx)	Food & beverage	1.35	PF	A	Yes	FDA EPDM	Best inbound stock we see; sugars rinse clean
Orange juice concentrate	Food & beverage	1.33	PF	A	Yes	FDA Viton	Citrus oil fraction can scent the bottle
Grape juice concentrate	Food & beverage	1.34	PF	A	Yes	FDA EPDM	Watch for tartrate scale at the outlet
Liquid sugar / sucrose syrup	Food & beverage	1.33	PF	A	Yes	FDA EPDM	Hot rinse only, no caustic needed
High-fructose corn syrup	Food & beverage	1.38	PF	A	Yes	FDA EPDM	Viscous; 3" outlet helps decanting
Molasses	Food & beverage	1.42	PF	A	Yes	FDA EPDM	Heated rinse; heavy heel
Honey	Food & beverage	1.42	PF	A	Yes	FDA EPDM	Crystallises; heater jacket recommended
Maple sap	Food & beverage	1.02	PF	A	Yes	FDA EPDM	Benign but sugars feed biofilm fast
Maple syrup	Food & beverage	1.33	PF	A	Yes	FDA EPDM	Hot rinse; inspect lid seat
Apple cider	Food & beverage	1.05	PF	A	Yes	FDA EPDM	Vented lid essential — ferments
Wine / must	Food & beverage	1.08	PF	A	Yes	FDA EPDM	Tartrate scale; usually leased
Beer / wort	Food & beverage	1.05	PF	A	Yes	FDA EPDM	Stainless preferred for repeat service
Brine (pickling liquor)	Food & beverage	1.20	PF	A	Yes	FDA Viton	Check cage for chloride attack
Vinegar, 10%	Food & beverage	1.01	PF	A	Yes	FDA EPDM	Easy; acid-resistant seal needed
Soy sauce	Food & beverage	1.20	PF	A	Yes	FDA Viton	Salt plus colour; monitor ghosting
Edible soybean oil	Food & beverage	0.92	P2	A	Yes	FDA Viton	140°F minimum or fat re-deposits
Edible canola oil	Food & beverage	0.91	P2	A	Yes	FDA Viton	As above
Olive oil	Food & beverage	0.92	P2	A	Yes	FDA Viton	Polyphenols can tint the wall
Glycerine, USP	Food & beverage	1.26	PF	A	Yes	FDA EPDM	Often effectively first-use stock
Propylene glycol, food grade	Food & beverage	1.04	PF	A	Yes	FDA EPDM	Frequently single-product filler stock
Liquid egg	Food & beverage	1.04	PF	A	Case by case	FDA EPDM	Protein film needs verification
Milk / dairy intermediate	Food & beverage	1.03	PF	A	Case by case	FDA EPDM	Allergen changeover record required
Whey concentrate	Food & beverage	1.06	PF	A	Case by case	FDA EPDM	Protein scale; hot detergent
Tomato paste	Food & beverage	1.10	PF	A	Yes	FDA Viton	Acidic; stains but rinses
Fruit purée	Food & beverage	1.12	PF	A	Yes	FDA EPDM	Pulp load; coarse settling matters
Flavour concentrate / essence	Food & beverage	0.95	Refused	Rebottle	No	PTFE	Permeates HDPE permanently — use stainless
Citrus terpene oil	Food & beverage	0.84	Refused	Recycle	Never	PTFE	One batch ends a poly bottle's usefulness
Spent grain slurry	Food & beverage	1.05	P2	B	No	EPDM	By-product duty; 3" outlet strongly advised
Yeast slurry	Food & beverage	1.08	P2	B	Case by case	EPDM	Vent — active fermentation
UAN 32 liquid nitrogen	Agricultural	1.32	P1	B	Never	EPDM	Rinses readily; dense — check ratings
UAN 28	Agricultural	1.28	P1	B	Never	EPDM	As above
Liquid starter 10-34-0	Agricultural	1.38	P1	B	Never	EPDM	Polyphosphate scale at the outlet
Ammonium thiosulphate	Agricultural	1.33	P1	B	Never	EPDM	Sulphur odour persists faintly
Potassium thiosulphate	Agricultural	1.47	P1	B	Never	EPDM	Very dense; 275 format only
Calcium nitrate solution	Agricultural	1.43	P1	B	Never	EPDM	Crystallises when cold
Humic / fulvic acid	Agricultural	1.10	P2	B	Never	EPDM	Dark staining, usually washes out
Fish hydrolysate fertiliser	Agricultural	1.12	P3	C	Never	Viton	Odour frequently permanent
Foliar micronutrient blend	Agricultural	1.25	P1	B	Never	EPDM	Metal salts can tint the wall
Glyphosate concentrate	Agricultural	1.17	P3	C	Never	Viton	Labelled rinse programme governs
2,4-D amine concentrate	Agricultural	1.19	Refused	Per label	Never	Viton	Label prescribes rinse-and-destroy
Crop oil adjuvant	Agricultural	0.88	P3	C	Never	Viton	Attacks EPDM; permeates slowly
Surfactant adjuvant (NIS)	Agricultural	1.03	P1	B	Never	EPDM	Foams heavily on transfer
Molluscicide suspension	Agricultural	1.22	Refused	Per label	Never	Viton	Refused — labelled destruction
Livestock drinking water	Water & inert	1.00	P1	A	Yes	EPDM	Effectively first-use
Irrigation water	Water & inert	1.00	P1	A	Yes	EPDM	May carry silt; coarse settling
Sodium hydroxide 50%	Industrial chemistry	1.52	P1	B	Never	EPDM	3,497 lb filled — check every rating
Sodium hydroxide 25%	Industrial chemistry	1.27	P1	B	Never	EPDM	Easy wash; dilute and drain
Potassium hydroxide 45%	Industrial chemistry	1.46	P1	B	Never	EPDM	As NaOH; dense
Sulphuric acid 93%	Industrial chemistry	1.83	Refused	Dedicated	Never	PTFE	4,182 lb filled; dedicated service only
Sulphuric acid 35%	Industrial chemistry	1.26	P1	C	Never	PTFE	Fume attack on cage galvanising
Hydrochloric acid 31%	Industrial chemistry	1.16	P1	C	Never	PTFE	Cage usually the limiting factor
Phosphoric acid 75%	Industrial chemistry	1.58	P1	B	Never	PTFE	Dense; viscous at low temperature
Nitric acid 42%	Industrial chemistry	1.26	Refused	Dedicated	Never	PTFE	Oxidiser — embrittles HDPE
Hydrogen peroxide 35%	Industrial chemistry	1.13	P1	B	Case by case	PTFE	Vent; absolutely no contaminants
Sodium hypochlorite 12%	Industrial chemistry	1.21	P1	B	Never	EPDM	Degasses; vent and shield from UV
Ferric chloride 40%	Industrial chemistry	1.42	P2	C	Never	Viton	Heavy orange staining is permanent
Aluminium sulphate	Industrial chemistry	1.33	P1	B	Never	EPDM	Scale at the outlet boss
Polyaluminium chloride	Industrial chemistry	1.35	P1	B	Never	EPDM	Gels if allowed to dry out
Propylene glycol coolant	Industrial chemistry	1.04	P1	B	Never	EPDM	Ideal duty; nothing to watch
Ethylene glycol	Industrial chemistry	1.11	P1	B	Never	EPDM	Toxic — never re-grade for potable
Calcium chloride brine 32%	Industrial chemistry	1.38	P1	B	Never	Viton	Chloride attack on lower cage
Magnesium chloride de-icer	Industrial chemistry	1.32	P1	B	Never	Viton	As above; rinse frames each spring
Potassium acetate de-icer	Industrial chemistry	1.28	P1	B	Never	EPDM	Benign; airport runway chemistry
Urea solution (DEF)	Industrial chemistry	1.09	P1	B	Never	EPDM	Purity-critical next fill; usually dedicated
Nickel plating solution	Industrial chemistry	1.25	Refused	Recycle	Never	Viton	Metal-bearing; never re-used
Chromic acid solution	Refused	1.30	Refused	Refused	Never	PTFE	Not accepted at the gate
Cyanide plating bath	Refused	1.15	Refused	Refused	Never	PTFE	Acutely hazardous — licensed facility only
Phosphate conversion coating	Industrial chemistry	1.22	P2	C	Never	Viton	Scale and staining
Amine corrosion inhibitor	Industrial chemistry	0.98	P2	B	Never	Viton	Fish-like odour can persist
Sodium silicate	Industrial chemistry	1.39	P3	C	Never	EPDM	Sets hard if dried; wash promptly
Polymer flocculant emulsion	Industrial chemistry	1.02	P3	C	Never	EPDM	Extremely slippery; gels with water
Sodium bisulphite	Industrial chemistry	1.33	P1	B	Never	EPDM	Sulphur odour; vent
Antifoam silicone emulsion	Industrial chemistry	1.00	P3	C	Never	Viton	Film is very hard to remove
Latex paint, white	Coatings & inks	1.30	P3	C	Never	EPDM	Heavy ghosting; often rebottle
Latex paint, tinted	Coatings & inks	1.32	P3	C	Never	EPDM	Pigment ghosting permanent
Water-based pigment dispersion	Coatings & inks	1.25	P3	C	Never	EPDM	Strong colour transfer into the wall
Flexographic ink	Coatings & inks	1.08	P3	Rebottle	Never	Viton	Resin binder plasticises the surface
UV-curable coating	Coatings & inks	1.10	Refused	Recycle	Never	PTFE	Cures in the bottle; not washable
Acrylic adhesive emulsion	Coatings & inks	1.08	P3	Rebottle	Never	EPDM	Caustic at 180°F, often still ghosts
PVA wood adhesive	Coatings & inks	1.09	P3	C	Never	EPDM	Wash before it skins over
Polyurethane resin, 2-part	Coatings & inks	1.12	Refused	Recycle	Never	PTFE	Cross-linked; nothing shifts it
Asphalt emulsion	Coatings & inks	1.01	P3	C	Never	Viton	Hot caustic plus long dwell
Concrete release agent	Coatings & inks	0.89	P2	C	Never	Viton	Oily film; 140°F detergent
Mineral oil, hydraulic	Oils & fuels	0.88	P3	B	Never	Viton	Permeation; faint odour often remains
Cutting fluid, soluble	Oils & fuels	0.92	P3	B	Never	Viton	Bacterial odour is the real problem
Gear oil	Oils & fuels	0.90	P3	C	Never	Viton	Heavy film; two cycles common
Used motor oil	Refused	0.89	Refused	Recycle	Never	Viton	Waste stream — not accepted for reuse
Diesel fuel	Oils & fuels	0.85	Refused	Recycle	Never	Viton	Permanent odour; bottle compromised
Kerosene	Oils & fuels	0.81	Refused	Recycle	Never	Viton	As diesel
Biodiesel B100	Oils & fuels	0.88	P3	C	Never	Viton	Solvency attacks some HDPE grades
Vegetable-based lubricant	Oils & fuels	0.92	P2	B	Never	Viton	Oxidises to a varnish if left
Anionic surfactant concentrate	Cleaning & sanitation	1.05	P1	B	Never	EPDM	It is soap — rinses, but foams
Non-ionic surfactant	Cleaning & sanitation	1.03	P1	B	Never	EPDM	Easy wash
Alkaline degreaser	Cleaning & sanitation	1.10	P1	B	Never	EPDM	Compatible with our own loop
Acid descaler	Cleaning & sanitation	1.14	P1	B	Never	PTFE	Segregate heel from caustic tanks
Quaternary ammonium sanitiser	Cleaning & sanitation	1.01	P1	B	Case by case	EPDM	Residual actives need verification
Peracetic acid sanitiser	Cleaning & sanitation	1.12	P1	B	Case by case	PTFE	Oxidiser; vent and shield
Hand sanitiser (ethanol 70%)	Cleaning & sanitation	0.87	P1	B	Case by case	Viton	Alcohol flashes off; little residue
Laundry detergent, liquid	Cleaning & sanitation	1.06	P1	B	Never	EPDM	Optical brighteners can tint
Car wash soap concentrate	Cleaning & sanitation	1.04	P1	B	Never	EPDM	Very common inbound stock
Floor finish / wax emulsion	Cleaning & sanitation	1.02	P3	C	Never	EPDM	Films hard; wash before it dries
Potable water	Water & inert	1.00	P1	A	Yes	FDA EPDM	Frequently first-use stock
Deionised water	Water & inert	1.00	P1	A	Yes	FDA EPDM	Best-value first-use source
Distilled water	Water & inert	1.00	P1	A	Yes	FDA EPDM	As above
Glycerine, technical	Water & inert	1.26	P1	B	No	EPDM	Technical grade is not food grade
Saline solution, industrial	Water & inert	1.07	P1	B	Never	Viton	Chloride; inspect cage
Unknown or mixed residue	Refused	—	Refused	Refused	Never	—	Safety assessment, not a grading question
RCRA P-listed residue	Refused	—	Refused	Refused	Never	—	Licensed treatment facility only
Radiological material	Refused	—	Refused	Refused	Never	—	No testing, no discussion
Pesticide, labelled destruction	Refused	—	Refused	Refused	Never	—	Service life ended by regulation

Field diagnosis

Read the gasket, not the puddle

Hardened and shiny: heat-aged or ozone-attacked. Replace, and consider shading the container.
Swollen and soft: chemically attacked. Replace with a different elastomer — the material was wrong, not worn.
Permanently flattened: compression set from over-torquing or years under load. Normal wear; replace routinely.
Cracked at the inner edge: mechanical, usually from a valve cross-threaded on. Check the boss thread before refitting.
Clean and sound but still weeping: the sealing face is the problem. Inspect the boss for scoring and the valve flange for warp.
Still leaking after a new gasket, new valve and a clean boss: you are in the 6% and the decision becomes rebottle or recycle.

How often should a gasket be replaced?

Every time the valve comes off and at every change of product. For containers in continuous service, annually as routine maintenance.

Vented or solid lid?

Vented for anything pumped, fermenting or stored outdoors. Solid for sealed transport and DOT closures.

Why did my gasket swell?

Chemical attack — classically EPDM in aromatics, fuels or fats. It absorbs, swells, loses its set and will not seal again.

Are your gaskets food-safe?

We stock FDA-compliant EPDM, silicone and Viton alongside industrial grades. Compliance references ship with the order.

What happens if I use a solid lid with a pump?

The bottle draws inward until a wall panel buckles permanently. We see several a year and they rarely recover past Grade C.

Can I reuse a gasket after cleaning a tote?

Please do not. It is the single most common cause in our whole dataset, and the saddest because the container was otherwise looked after.

Lids, seals and the compatibility table you should bookmark

Get the right elastomer first time

Lids: vented or solid

Seals and caps

Diagnosing a seal failure in the field

Lid & gasket FAQ

Related pages

Valves & fittings

Pallets & cages

Food-grade totes

Twenty-one media, four elastomers, one hundred prior products

Which seal each prior product needs

Read the gasket, not the puddle

How often should a gasket be replaced?

Vented or solid lid?

Why did my gasket swell?

Are your gaskets food-safe?

What happens if I use a solid lid with a pump?

Can I reuse a gasket after cleaning a tote?