Chlorine is the service where the wrong answer shows up fastest. Dry chlorine and stainless steel get along at room temperature. Add water — even the moisture that condenses out of a line overnight — and the same gas becomes hydrochloric and hypochlorous acid sitting against the corrugation valleys.
What this service does to a hose
The switch is moisture, not concentration. Wet chlorine pits austenitic stainless quickly, and because the chloride ion is present it also drives stress corrosion cracking — the fine, branching, brittle cracks that run through the wall with no thinning alongside them. Our failure modes page shows what that looks like next to ordinary fatigue. There is no grade of stainless in our range that solves it. 316L lasts longer than 304L. Neither lasts.
The second mechanism is heat. Chlorine and steel react directly once the metal gets hot enough, and that reaction sustains itself. It is not a corrosion problem, it is a fire, and it is the reason chlorine lines are kept cool and dry as a matter of design rather than good practice.
What we would fit
A PTFE-lined stainless assembly. The liner carries the chlorine and the metal never touches it. The stainless corrugated hose and braid outside the liner do what they are good at — hold the pressure, absorb the movement, and protect the liner from everything happening in the plant.
| Element | What we would supply | Why |
|---|---|---|
| Liner | PTFE, smooth bore or convoluted to suit the bend radius | Chemically inert to wet and dry chlorine |
| Hose | 316L annular corrugated | Pressure containment and movement, kept off the medium |
| Braid | 316L, single or double to the pressure | Carries the pressure thrust |
| Ends | Flanged as standard; tell us the face and rating | Bolted joints are easier to inspect than threads on this duty |
| Marking | Direction marked on every lined assembly | A liner fitted backwards chatters and eventually detaches |
What we would not fit, and what happens
Bare stainless of any grade for wet chlorine. Our own media table marks it X for a reason. It will work for a while, which is the dangerous part.
Interlock hose. The seam is mechanical, so the medium passes straight through it. Interlock is not pressure-tight and never has been. See interlock construction if that is not obvious.
What we need to size it
| We need | Because |
|---|---|
| Wet or dry, and how you know | It changes the whole answer, not a detail of it |
| Temperature — medium and ambient | The PTFE sets a ceiling well below the stainless |
| Working pressure, and any vacuum | A liner behaves differently under vacuum than under pressure |
| Whether the hose moves in service | Loading and unloading hoses flex; fixed jumpers do not |
| End connections, both ends | And whether either end can be fitted the wrong way round |
Read next
PTFE-Lined Assemblies
Construction, smooth bore against convoluted, and where the liner sets the limit.
View →Media Compatibility
Twenty-three media rated against 304L and 316L, with the reason where it matters.
View →Failure Modes
What chloride cracking looks like on the part, and how to tell it from fatigue.
View →