What is a top entry ball valve?

A ball valve whose body is in one piece and whose ball, seats and stem are fitted through a bolted bonnet on top. It can be serviced from above without cutting the body out of the line.

What is the difference between top entry and side entry ball valves?

A side entry valve has a body joint on the side and is usually taken out of the line to reach the seats. A top entry valve has one body piece and a top bonnet, so the internals come out from above while the body stays in the line.

Can a top entry ball valve be repaired in the line?

The bonnet, ball, seats and seals can be removed from above with the body still in the line, once the line is isolated and drained and there is enough space. The bonnet gasket is renewed and the bolting tightened to the maker’s figure before the valve is tested.

What does API 6D cover?

API 6D covers the design, manufacture, testing and documentation of pipeline and piping valves, including ball valves. It sets pressure test and record requirements; the pressure–temperature ratings come from ASME B16.34.

Draft page. The factory document pack for this page is still under review. Values marked “To be confirmed” have not been verified yet.

Top entry ball valves

Ball valves · API 6D

A top entry ball valve has a one-piece body with a bolted bonnet on top, so the ball, seats and stem can be removed for repair without cutting the valve out of the line. The design suits welded pipelines and large sizes where in-line maintenance access matters.

Who makes this valve

Signed panel factories with API 6D in force4

How licences are checkedExpiry date in the API Composite List, not the “Active” flag

Registry checked8 Nov 2026Next check 8 Feb 2027

Manufacturer and licence no.Named in your quotation, with the registry link

We publish one number per API specification, never a factory-by-factory row: a row with its licence set and expiry year would point at a single registry entry. One RFQ is quoted by several panel factories, and each quotation names the manufacturer, its API licence number and where to verify it, so you can check the source before you order. How we check licences

How it compares

Side entry vs top entry vs fully welded ball valve: body design and access (general)
Feature	Side entry	Top entry	Fully welded
Body construction	Two- or three-piece body with a bolted body joint	One-piece body with a bolted bonnet on top	Welded body with no bolted body joint
Access to ball and seats	Through the body joint, usually with the valve removed from the line	Through the top flange while the valve stays in the line	Not intended for seat replacement in the field
Joints that can leak	One or two body joints plus the stem seal	Bonnet joint plus the stem seal	Welds plus the stem seal
Typical use	General process and utility service	Welded pipelines, large sizes, hard-to-reach locations	Buried lines and district heating

Specification range

Grades listed are common ASTM designations for this valve type. The size and class range offered by the partner factory is confirmed against its datasheet before this page goes live.

Top entry ball valve specification: size × pressure class × ASTM grade
ASTM grade	Form	Sizes (NPS)	Pressure classes	End connections	Partner factory supplies
ASTM A216 WCB	Cast carbon steel body	To be confirmed	To be confirmed	To be confirmed	To be confirmed
ASTM A105	Forged carbon steel body	To be confirmed	To be confirmed	To be confirmed	To be confirmed
ASTM A350 LF2	Forged low-temperature carbon steel	To be confirmed	To be confirmed	To be confirmed	To be confirmed
ASTM A351 CF8M	Cast 316 stainless steel	To be confirmed	To be confirmed	To be confirmed	To be confirmed
ASTM A182 F316	Forged 316 stainless steel	To be confirmed	To be confirmed	To be confirmed	To be confirmed

Pressure–temperature rating (ASME B16.34)

The body material and the pressure class together set the maximum working pressure at each temperature. The table shows ASME B16.34 Standard Class values for material group 1.1 (for example WCB and A105) at −29 °C to 38 °C. Seat and seal materials can set a lower limit than the shell rating.

ASME B16.34 Standard Class, Group 1.1, −29 °C to 38 °C. Shell rating only; the valve rating can be lower because of seat and seal materials.
Pressure class	Max. working pressure (bar)	(psi)
Class 150	19.6	285
Class 300	51.1	740
Class 600	102.1	1,480
Class 900	153.2	2,220
Class 1500	255.3	3,705
Class 2500	425.5	6,170

Partner factory P-T curve for this valve: To be confirmed

How a top entry valve is assembled

The body is a single casting or forging with a machined top opening. The bonnet carries the stem and is bolted to the body over a gasket or O-ring seal, and the ball, seats and seat springs sit in the body cavity. API 6D sets the design, material and test requirements for the valve, including the body joint and the pressure tests after assembly.

In-line repair means removing the bonnet, lifting out the ball and seats and fitting new seals. The bonnet gasket is renewed, the bolting is tightened to the specified torque and the valve is pressure tested before it returns to service. Whether a valve can be serviced this way depends on its design and on the space above it.

Cast and forged body materials

Top entry bodies are made as castings or forgings. Carbon steel bodies commonly use ASTM A216 WCB castings or ASTM A105 forgings; low-temperature service uses impact-tested grades such as ASTM A350 LF2, and stainless bodies use ASTM A351 CF8M castings or ASTM A182 F316 forgings.

The grade on the datasheet and the grade on the EN 10204 3.1 certificate must match, and the certificate should state the heat number so the body can be traced to the test record.

Testing and documents to request

After assembly the valve is pressure tested with a hydrostatic shell test and a seat test, per API 6D or per API 598 where the purchase order names it. Ask for the test procedure and the test record for the serial number you receive.

For buried or offshore service, add the coating and marking records to the material certificates and the pressure test record.

Fire-safe design and fugitive emissions

A fire test is a type test of a design, not a test of every valve. API 607 and ISO 10497 burn a valve with its seats and seals and then check that it still isolates; the certificate has to cover the valve type, size range and design you are buying.

ISO 15848-1 covers fugitive emissions from the stem seal, with tightness classes measured before and after mechanical and thermal cycles. A low-emission specification should state the class, the standard and the cycle count.

No fire-test or emission-test certificate for a partner factory valve is published on this page.

Datasheet and drawings

Datasheet: To be confirmed

A datasheet, dimension drawing and STEP file will be published here, without factory branding, after the panel factory authorises them. Until then, ask for them in your RFQ.

Prices, lead times and minimum order quantities are quoted per enquiry against the datasheet you send; they are not listed on this page.

Frequently asked questions

What is a top entry ball valve?: A ball valve whose body is in one piece and whose ball, seats and stem are fitted through a bolted bonnet on top. It can be serviced from above without cutting the body out of the line.
What is the difference between top entry and side entry ball valves?: A side entry valve has a body joint on the side and is usually taken out of the line to reach the seats. A top entry valve has one body piece and a top bonnet, so the internals come out from above while the body stays in the line.
Can a top entry ball valve be repaired in the line?: The bonnet, ball, seats and seals can be removed from above with the body still in the line, once the line is isolated and drained and there is enough space. The bonnet gasket is renewed and the bolting tightened to the maker’s figure before the valve is tested.
How is a top entry ball valve tested?: It is pressure tested after assembly, normally with a hydrostatic shell test and a seat test per API 6D, or per API 598 where the purchase order names it. Ask for the test record for the serial number and the EN 10204 3.1 material certificates.
What does API 6D cover?: API 6D covers the design, manufacture, testing and documentation of pipeline and piping valves, including ball valves. It sets pressure test and record requirements; the pressure–temperature ratings come from ASME B16.34.

Standards cited

API Spec 6D: Pipeline and piping valves: design, manufacture, testing and documentation of ball, gate, plug and check valves.
ASTM A216: Carbon steel castings suitable for fusion welding for high-temperature service; grade WCB is common for valve bodies.
ASTM A105: Carbon steel forgings for piping applications.
ASTM A350: Carbon and low-alloy steel forgings that require notch toughness testing for low-temperature service.
ASTM A351: Austenitic stainless steel castings for pressure-containing parts; grades CF8 and CF8M are common for valve bodies.
ASTM A182: Forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts for high-temperature service.
EN 10204: Types of inspection documents, including the 3.1 and 3.2 certificates.
API Std 598: Valve inspection and pressure testing (shell, backseat and seat).
API Std 607: Fire test for quarter-turn valves with non-metallic seats: a type test of the design.
ISO 10497: Fire type-testing requirements for valves: test procedure and acceptance criteria.
ISO 15848-1: Fugitive emissions: measurement, test and qualification procedures for valve stem seals, with tightness classes from a type test.
ASME B16.34: Valves with flanged, threaded and welding ends: pressure–temperature ratings by material group and pressure class. Edition quoted to: ASME B16.34-2025.