Fittings & options
Every fitting, gasket and bolt on a sulfuric acid tank has to resist the acid at your concentration. We specify and install them at our Willis, Texas plant so the tank arrives ready to connect.
The rules
PVC, CPVC, polypropylene, HDPE and PVDF fittings are all rated Excellent. See the chart.
PVDF fittings are rated Excellent and HDPE Good. PVC is severely attacked; CPVC and polypropylene drop to Fair.
Viton® is rated Excellent at every concentration. EPDM is Good above 10%; Buna-N falls to Fair above 75%.
Hastelloy is rated Good throughout. Avoid 316 stainless above 10% and titanium at any strength.
No welded flanges in the sidewall. We do not install welded flanges in the sidewalls of tanks storing sulfuric acid or other oxidizers. We use bulkheads and bolted flanges instead.
Connections

The most common tank connection, sealed with a Viton® gasket. PVC, CPVC or polypropylene up to 75%; PVDF above 75%.

A bolted flange through the tank wall, used in place of a welded flange in sulfuric acid service.

Seals on the curved dome for top-of-tank connections such as fill and vent lines.
Flow & venting

True-union and compact ball valves in materials matched to your concentration.

Atmospheric tanks must vent. Concentrated acid absorbs moisture from the air, so ask us about vent options for your site.

Fill from ground level through a line that runs up the sidewall and enters the top of the tank.
Monitoring

Non-contact level measurement that never touches the acid, with an optional display and controller.

A simple, non-electric gauge that shows the liquid level on the outside of the tank.

For double wall tanks: a probe between the walls sounds an alarm, flashes a strobe and can signal your PLC.
Protection

Closed-cell polyurethane foam rated R-6.7 per inch. 2″ standard; 3″ and 4″ available. See insulated sulfuric acid tanks.

Heat trace pads and a controller keep concentrated acid from freezing in cold weather. Why acid freezes.

Galvanized cable tie-down systems for vertical tanks under 5,000 gallons, rated for 120 mph winds. See the installation guide.
Tank, fittings, gaskets and hardware all need to be rated for your concentration.