Sanitary Manways: Opening Type and Pressure Rating

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Match cover to pressureOpening and rating. Specify seal, finish, entryHygiene and safety.

Match the cover type to the tank pressure

Alfa Laval's leaflet for its inward-opening oval cover LKD 535 × 435, used on dairy tanks, gives a maximum static pressure of 36 psi (250 kPa), a test pressure of 54 psi (375 kPa), a maximum positive working pressure of 0 psi and a maximum negative working pressure of 7 psi (50 kPa); the cover turns into the tank for inspection and its seal is positioned so that tank pressure does not affect it. [1] Its Type O oval covers, for openings below liquid level, list calculated static-tank pressures of 19 to 58 psi depending on size, with inward, outward or side-swing versions. [2]

For pressurised tanks, Alfa Laval's outward-opening circular HLSD-2 is secured by swing bolts, rated for full vacuum and approved for pressure vessels under PED 2014/68/EU up to hazard category IV; its maximum allowable pressure depends on size, number of bolts and design temperature, and the cover is not pressure tested on its own but must be tested as part of the vessel. In its selection table the 17.72 in cover is rated 75.4 psi at 122 °F and 59.5 psi at 482 °F with 6 bolts, and 126.2 psi at 122 °F with 10 bolts. [3]

Editorial calculation: 75.4 psi ≈ 5.2 bar and 59.5 psi ≈ 4.1 bar, so the same 6-bolt cover loses 21% of its rating at the higher temperature; a tank designed for 6 bar at 122 °F would need the 10-bolt version (126.2 psi ≈ 8.7 bar). The LKD's 7 psi vacuum rating is about 0.48 bar. Tank pressures are assumed examples; match the cover to the vessel's design pressure, vacuum and temperature, including CIP and SIP conditions.

Give the supplier the tank type and volume, mounting position (top or side, above or below liquid level), required opening size and shape, inward or outward opening and hinge side, design pressure, vacuum and temperature (including CIP/SIP), product and cleaning chemicals, seal material, surface finish, certificates (3.1, PED, FDA, 3-A, ASME BPE) and options such as sight glass, safety grid or opening spring.

Specify seals, finish and safe entry

Alfa Laval lists seal options of EPDM, NBR, FPM or silicone for its oval covers and EPDM, FPM, silicone and FEP- or PFA-covered elastomers for HLSD-2, with an FDA §177.2600 declaration for seal material. Product-wetted surfaces are specified at Ra 32 µin, with 1.4404 (316L) wetted steel parts on HLSD-2 and 304 or 316L on the LKD; the LKD's NBR seal limits it to −4 to +194 °F, while HLSD-2 lists 14 to 482 °F. [1] [3]

OSHA's permit-required confined space standard (29 CFR 1910.146) defines a confined space as one large enough to enter bodily, with limited or restricted means of entry or exit, and not designed for continuous occupancy, and names tanks and vessels as examples. [4] Editorial note: if people will enter the tank through the manway, size the opening, hinge and any safety grid for the employer's entry and rescue procedures, and ask whether the cover can be locked open or closed.

Oval, circular and sight-glass covers from two valve makers

China Sanitary Valve and Jianen Sanitary are the two companies shown below; neither card states a pressure rating, so ask both for the figures Alfa Laval publishes.

Listings include oval inward manways, circular and elliptical manhole covers and covers with sight glasses from sanitary valve makers, and sanitary manways among sanitary fittings, valves and tank accessories. Ask each for pressure and vacuum ratings at temperature, seal compounds and material certificates.

Frame, cover, seal, hinge, bolts and options

The rows follow the two Alfa Laval designs above: a handle closes the inward LKD, swing bolts clamp the outward HLSD-2.

Part	Role	Fix in the order
Frame	Welded into the tank shell or head. [3]	Shape, height, conical frame.
Cover (lid)	Closes the opening; inward or outward. [1] [3]	Thickness and material.
Seal	Gas- and liquid-tight closure. [1] [3]	Compound and FDA status.
Hinge	Locates cover; limits opening. [3]	Rigid or double hinge; side.
Swing bolts or handle	Clamp the cover. [3] [1]	Number of bolts; handle.
Options	Sight glass, safety grid, spring. [3]	Options required.

Opening size, pressure, temperature, finish and seal for the quotation

Tank pressure, vacuum and cleaning temperatures come from your vessel design. Alfa Laval values appear in the middle column as examples of how a maker states them.

Field	What it means and published values	Ask the supplier for
Nominal Diameter (mm)	Examples: 7.87–23.62 in circular; 535 × 435 mm oval. [3] [1]	Clear opening.
Operating Pressure (MPa)	Example: 0 kPa positive working (inward LKD). [1]	Positive and vacuum ratings.
Operating Temperature (°C)	Examples: −4 to +194 °F (NBR); 14 to 482 °F. [1] [3]	Range with chosen seal.
Surface Roughness (Product Contact) (μm Ra)	Example: Ra 32 µin (≈ 0.8 µm). [1]	Ra and polishing method.
Leakage Rate (cm³/min)	Tightness by seal and bolts. [3]	Test method.
Material Grade	Example: 316L wetted, 304 other parts. [3]	Grades and 3.1 certificate.
Gasket Material	Examples: EPDM, NBR, FPM, silicone, FEP/PFA-covered. [1] [3]	Compound and FDA status.
Closure Type	Handle (inward) or swing bolts (pressure). [1] [3]	Closure and bolt count.
Weight (kg)	Example: 18.5 lb (LKD 535 × 435). [1]	Weight.
Pressure Rating	Depends on size, bolts and temperature. [3]	Selection table value.

Send the tank, pressure and hygiene data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Tank: [type; volume; top or side mounting]
Opening: [shape; size; inward/outward; hinge side]
Pressure: [design pressure; vacuum; temperature incl. CIP/SIP]
Hygiene: [seal compound; Ra; certificates]
Entry: [confined-space entry; safety grid]
Options: [sight glass; spring; lock]

See manufacturer records Send an enquiry through CNFX

Compare sanitary manway suppliers

2 companies list this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

China Sanitary Valve

Manufacturing site to be confirmed for the order

Lists oval inward manways, circular and elliptical manhole covers and covers with sight glasses.

Product scope checked 2026-10-11

Current product source ↗

Manways listed · profile compiled by CNFX from public sources

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Jianen Sanitary

Manufacturing site to be confirmed for the order

Lists sanitary manways among sanitary valves, fittings, pumps and tank accessories.

Product scope checked 2026-10-11

Current product source ↗

Manways listed · profile compiled by CNFX from public sources

View profile Send enquiry

Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review · Page last updated 13 October 2026

Buyer questions

Can an inward-opening manway hold tank pressure?

Alfa Laval's inward-opening LKD 535 × 435 is rated 0 psi positive working pressure and 7 psi vacuum; pressure tanks use outward-opening bolted covers. [1] [3]

Why does a manway's pressure rating change with temperature?

Alfa Laval's HLSD-2 selection table rates the 17.72 in, 6-bolt cover at 75.4 psi at 122 °F but 59.5 psi at 482 °F. [3]

Is entering a tank through a manway confined-space work?

OSHA 29 CFR 1910.146 names tanks and vessels as examples of spaces with limited means of entry or exit. [4]

Sources and what still needs a direct check

Sources checked 2026-10-11. Alfa Laval's leaflets describe its own covers and are examples of how ratings are stated. OSHA 29 CFR 1910.146 is US regulation for permit-required confined spaces.

Alfa Laval — Access tank cover, oval cover type LKD 535 × 435, US product leaflet (distributor-hosted) ↗ Maker product leaflet Return to text ↑
Alfa Laval — Access tank cover, oval type O, US product leaflet (distributor-hosted) ↗ Maker product leaflet Return to text ↑
Alfa Laval — Tank covers, circular (HLSD-2 and others), US product leaflet ↗ Maker product leaflet Return to text ↑
eCFR — 29 CFR 1910.146 Permit-required confined spaces ↗ Regulation Return to text ↑

Still to check yourself

Match cover type to positive and vacuum pressure.
Check the rating at your highest temperature.
Confirm seal compound and FDA status.
Plan confined-space entry through the opening.
Verify the legal supplier and factory.

Sanitary manway (hygienic tank manhole cover)