A strip curtain runs five to ten years. The rail above it often does not.
We replace more hangers and rails than strips. The reason is rarely a bad strip. It is the wrong metal for the room it hangs in.
Choose stainless |
Choose galvanised |
| Washdown, cold rooms, food and pharma, coastal sites, chemical areas. 316 where chlorine is involved. | Dry warehouses, interior doorways, short leases, long rail runs where cost scales with length. |
What the two options actually are
♦Galvanised steel is mild steel with a zinc coating. Hot-dip gives 60–85 µm. Electroplated gives 5–12 µm. Ask which one, because the price difference is real and so is the service life.
♦Stainless steel is an alloy, not a coating. 304 carries roughly 18% chromium and 8% nickel. 316 adds molybdenum, which is what buys you chloride resistance.
♦Both are usually 1.5–2.0 mm thick in the rail, and 2–3 mm in the hanger.
Where each one fails
1. Galvanised fails at the edges. Cutting and drilling leave bare steel. That is where rust starts, and it spreads under the zinc.
Wet rooms bring white rust, the zinc oxide bloom that looks like chalk. Chlorides eat the zinc quickly. Ammonia and acids do the same.
2. Stainless fails by pitting. 304 will rust in a coastal plant or under repeated hypochlorite. It is not a maintenance-free material, whatever the catalogue says.
3. Powder coating is a third option, with a catch. Plasticiser migrates out of the strip and softens the coating where they rub. After a few years, the rail goes tacky and the paint lifts. Bare metal or stainless avoids it.
Side by side
Condition Galvanised 304 316
Dry warehouse, heated Good Excellent Excellent
Cold room, condensation Fair Good Excellent
Washdown, chlorinated foam Poor Fair Good
Coastal, salt air Poor Fair Good
Food and pharma areas Not advised Yes Yes
Relative cost, same profile 1 3–4 4–5
Span, load and sag
A 2 mm × 200 mm strip weighs about 0.54 kg per metre of drop. A 2 m doorway with ten strips puts roughly 11 kg on the rail, plus hardware.
Hanger centres should sit at 300–400 mm, never beyond 500 mm.
A 1.5 mm rail holds a 1.2 m span without visible sag. Past that, add a centre bracket. Past 3 m, step up to a heavier profile.
Sag is a load problem, not a grade problem. Stainless sags the same as galvanised at the same thickness.
The cost number buyers get wrong
♦Compare installed cost per doorway, not price per kilogram.
♦A galvanised rail that fails in year three costs the hardware again, plus labour, plus a shift of downtime. In a wet room, that usually beats the stainless quote.
♦In a dry warehouse, the reverse holds. Galvanised lasts ten years there, and stainless is money you never recover.
When galvanised is the right call
♦Distribution centres and dry storage.
♦Interior doorways without washdown.
♦Short-lease buildings and temporary partitions.
♦Long runs of rail where cost scales with length.
One condition: specify hot-dip, not electroplated, and ask for the zinc thickness in writing.
When stainless is the right call
♦Food, dairy, beverage and pharmaceutical plants.
♦Cold rooms and freezers, where condensation never stops.
♦Coastal sites and anything within a few kilometres of salt water.
♦Chemical and plating areas.
♦Tropical humidity, which is most of Southeast Asia.
304 covers most of these. Move to 316 when the cleaning chemicals contain chlorine, or when the plant sits near the sea.
What to write on the purchase order
1. Grade. 304 or 316. "Stainless" alone means nothing.
2. Coating. Hot-dip or electroplated, with zinc thickness in µm.
3. Steel thickness. Rail and hanger, in mm.
4. Salt spray hours. Ask for the test report, not the claim.
5. Fixings. Same metal family, or isolate with nylon washers. A stainless bolt in a galvanised rail makes the zinc corrode faster.
6. Profile. Match the strip width and the overlap you need.
7. Edges. Deburred. A sharp edge cuts strips and gloves.
Keeping it alive
♦Walk the doorways quarterly. Look at the hanger hooks, the fixing points, and the first 100 mm below the rail.
♦Red rust on galvanised means the zinc is gone in that spot. Wire-brush it and touch up with a zinc-rich paint. Ordinary paint will not protect the steel underneath.
♦Stainless needs less. Wash off salt and chemical residue, and do not leave chlorinated sanitiser sitting on it.
FAQ
Is 304 good enough for a food plant?
Usually yes. Move to 316 if the plant uses chlorinated sanitisers, or sits in a coastal area. Both grades are acceptable in food areas. Galvanised is not.
Can I mix stainless bolts with a galvanised rail?
Not in a wet room. The stainless stays bright while the zinc around it disappears. Use matching fixings, or isolate the joint with nylon washers.
How long does galvanised last?
Eight to twelve years indoors and dry. Two to four in a wet room. The gap is the whole argument.
Does thickness matter more than grade?
For sag over a long span, yes. Grade decides how long it survives. Get both right.
About the author
Written by the technical and export team at Baoding Yashen Technology Co., Ltd., Baoding, Hebei. Founded in 2013.
We make PVC curtain strips, PVC sheets, food-grade PVC wrap, phenolic rods, and the machinery that processes them. Our materials carry CE, FDA, RoHS, and REACH certification.
We ship to more than 100 countries, from Southeast Asia to the Americas and the Middle East.
We supply the whole chain: raw materials, machines, formulas. Hardware questions usually arrive with a photo of a rusted rail.
Send us the room conditions and the cleaning chemicals. We will tell you which grade to buy, and when the cheaper one is the better buy.
