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LRS Certificates in the context of marine butterfly valves refer to certifications issued by Lloyd’s Register of Shipping (LRS), a well-known maritime classification society. These certificates verify that the valves meet the standards required for marine applications, particularly for safety, reliability, and regulatory compliance.

What Is an LRS Certificate?

An LRS Certificate demonstrates that a product—like a butterfly valve—has been:

Inspected and tested by Lloyd’s Register or an authorized party.

Compliant with Lloyd’s marine classification rules.

Suitable for use on ships and offshore platforms.

What It Means for Marine Butterfly Valves

A butterfly valve with an LRS certificate has typically passed tests related to:

Criteria	Typical Requirements
Pressure rating	Confirmed for marine system pressures
Material quality	Approved corrosion-resistant materials
Fire safety	Fire-safe design (if required)
Functionality	Reliable operation under marine conditions
Leakage tests	Zero or acceptable leakage rates

Types of LRS Certificates

There are different types depending on what’s being certified:

Certificate Type	Description
Type Approval Certificate	Confirms a valve design meets LR rules. Valid for multiple units of the same design.
Inspection Certificate (3.2)	Confirms that each valve is individually tested and inspected (often project-specific).
Works Certificate	Provided by the manufacturer, verified by LR or its representative.

Why Is It Important?

Regulatory Compliance: Required for equipment used on LR-classed vessels.

Insurance and Safety: Helps in securing vessel insurance and ensuring safe operations.

Global Acceptance: LRS is recognized by maritime authorities worldwide.

How to Verify an LRS Certificate

Check the certificate number on the LRS website.

Request the Type Approval Certificate from the valve supplier.

Ensure the stamp or signature of Lloyd’s Register is present on the physical certificate.

DNV certification plays a vital role in marine butterfly valves, signifying that the product complies with the standards set by Det Norske Veritas (DNV, formerly DNV-GL). It is a key requirement for entering the international shipbuilding and offshore engineering markets.

1. What is DNV Certification?

DNV (Det Norske Veritas) is a world-leading classification society and risk management organization.
DNV certification is a third-party verification that a product meets DNV’s classification standards in terms of design, materials, manufacturing, testing, and quality control.
It is widely applied to ships, offshore structures, and energy equipment that demand high reliability and safety.

2. DNV Requirements for Marine Butterfly Valves

In the field of marine butterfly valves, DNV certification involves the following aspects:

1. Product Design and Drawing Approval

Valve designs must be submitted for review by DNV, including:

Structural drawings

Material specifications

Working pressure

Temperature range

Sealing structure and configuration

2. Material Certification

All pressure-bearing parts must use DNV-approved materials.
Material certificates conforming to EN 10204 3.1 or 3.2 are usually required.

3. Inspection of Castings or Forgings

DNV requires NDT (non-destructive testing) on valve bodies and discs, including:

Ultrasonic testing (UT)

Radiographic testing (RT)

Magnetic particle testing (MT) or dye penetrant testing (PT)
These inspections must be witnessed or reviewed by a DNV surveyor.

4. Performance Testing

Valves must undergo:

Shell pressure tests

Leakage/sealing tests
Typically carried out under the supervision of a DNV inspector.

For specific applications, additional tests may be required:

Low-temperature impact test

Fire safety test

Corrosion resistance tests (e.g., NACE standards)

5. Manufacturing Supervision and Final Acceptance

DNV monitors the manufacturing process.
A DNV-signed Product Certificate must be issued upon final acceptance.

3. Common Applications of DNV-Certified Marine Butterfly Valves

Onboard Ship Systems:

Seawater cooling systems

Ballast water systems

Fire-fighting pipelines

Offshore Platforms:

Living quarters

Oil & gas transfer pipelines

LNG and Liquid Cargo Ships:

Cryogenic butterfly valves

Bi-directional sealing butterfly valves

4. Importance of DNV Certification for Export

DNV certification is a passport to major global markets such as:

Europe, Norway, Germany, the Netherlands, Singapore, Japan, etc.

Many renowned shipyards (e.g., Hyundai, Samsung Heavy Industries, Fincantieri) require valves to be certified by DNV or other major classification societies such as ABS, BV, or LR.

5. Recommended Information for Your Promotion

If you are involved in the casting of valve bodies, discs, or shafts, you can include the following statement in your promotional materials:

Our marine butterfly valve parts (valve body, disc, and shaft) are made from DNV-approved materials and produced under ISO 9001 quality control. We support our clients to pass DNV product certification through strict casting quality and mechanical property assurance.

Fault	Cause Analysis	Solution
Leakage	Seat aging or wear	Replace seat
Difficult operation	Shaft rust or jamming	Clean,lubricate,or replace shaft
Corrosion perforation	Inadequate corrosion protection	Repair by welding or replace valve
Handle damage	Over-torque operation	Replace handle and add torque limiter

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.

We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Key Factors

• Seat Material Selection: EPDM for seawater, NBR for oil, VITON for high temperature.
• Machining Precision: Concentricity between valve body, disc, and seat.
• Installation Position: Horizontal installation is preferred over vertical to avoid self-weight affecting sealing.
• Torque Control: Excessive or insufficient torque may damage the seat.

Key Technical Points

• Ensure concentricityamong body, disc, and seat.
• Select suitable sealing materials.
• Prevent high-temperature aging of the seat.
• Apply anti-corrosion coatingsor linings to enhance seawater corrosion resistance.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.

We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!