When Do Liquid Level Gauges Need to Be SOLAS Compliant

Even the smallest component on a marine vessel can cause inspection failure. For example, if your liquid level gauge isn’t SOLAS compliant where it should be, the result can be project delays, extra costs, and questions over your crew’s safety.

The point of this article is to show you when SOLAS compliancy is required for liquid level gauges, what the standards mean in practice, and which Seetru gauges carry the approvals you need as a shipbuilder or engineer.

What is SOLAS?

SOLAS stands for the International Convention for the Safety of Life at Sea. It’s the main set of international rules that keep ships, crews, and passengers safe. The convention is managed by the International Maritime Organization (IMO), which is part of the United Nations.

The first version of SOLAS was first adopted in 1914 as a direct response to the Titanic disaster in 1912. However, it didn’t come into force in 1915 as originally planned due to the First World War.

An illustrated depiction of the Titanic sailing at night, surrounded by stars and an iceberg, with smoke billowing from its stacks.

Subsequent versions were adopted in 1929 (entered into force in 1933), 1948 (entered into force in 1965), and 1960 (entered into force in 1965). The current version in use is the SOLAS Convention of 1974, which was adopted on 1 November 1974 and came into force on 25 May 1980 after ratification by enough countries. This 1974 convention introduced a new amendment procedure that allows for faster updates to the rules.

Since the 1980s, the rules have been updated many times to cover modern shipping risks. Today, SOLAS covers almost every area of ship safety, from fire protection and lifeboats to structural design and, of course, equipment like liquid level gauges.

Why should this be important to you? If you’re building or running a ship, SOLAS is a legal requirement, and inspectors can check your gauges and other components during surveys. If a gauge should be SOLAS compliant and isn’t, the ship can be held back until the issue is fixed. That means time lost, additional cost, and possible reputational damage.

Treaties and international agreements - International Convention for the Safety of Life at Sea, 1974 .

Why do some Liquid Level Gauges Need to be SOLAS Compliant?

It really depends on the type of liquid the gauge is measuring and the safety risks involved. Which is why not all liquid level gauges on board a ship require to be SOLAS compliant.

If a gauge is used on tanks carrying flammable or hazardous liquids, like fuel or certain chemicals, it must adhere to SOLAS rules. These gauges need to meet tough international safety standards to make sure they won’t cause sparks or leaks that could lead to fires or explosions. They also have to be robust and reliable because a wrong reading could spell disaster for the vessel and crew.

That’s why gauges like Seetru’s G35 Seemag magnetic gauge or the G31 Seeflex reflex gauge come with multiple approvals from major classification societies. Making them SOLAS compliant. They’re designed specifically for those important high-risk applications.

On the other hand, gauges that measure less risky liquids or are used in different industries might not need to be SOLAS compliant.

For example, Seetru’s G21 Tubular Marine Gauge is a heavy duty liquid level gauge for marine and offshore industries. As it has a tubular design, this gauge is suitable for use with non-flammable liquids only. Therefore, it doesn’t need to be SOLAS compliant. It’s a liquid level gauge that is commonly used for water storage and coolant tanks on cargo ships, tugs and military ships.

Documented requirements focused on meeting SOLAS compliance for maritime safety and operational effectiveness.

What Does SOLAS Require from You and Your Liquid Level Gauges?

As previously covered, the International Convention for the Safety of Life at Sea requires that gauges on tanks holding flammable liquids, like fuel or hydraulic oils. Must be designed to prevent any risk of fire, explosion, or leaking dangerous substances. These gauges undergo rigorous tests to make sure they can operate well under harsh conditions. These tests cover pressure, wide temperature ranges, and exposure to vibration and rough seas.

The gauge’s construction is also checked to confirm it won’t fail or give false readings. That’s done because inaccurate level information could lead to overfilling, leaks, or unsafe operating conditions. Features like self-closing valves, sealed electrical parts, and robust mechanical design are essential requirements.

Additionally, SOLAS rules often require that gauges can be maintained or replaced in a safe manner while tanks are in service, without the risk of releasing cargo or fuel. Some gauges must also meet standards for explosion-proof electrical equipment (such as IEC 60079-series which covers safety requirements for electrical devices used in explosive atmospheres), depending on their design and location on the vessel.

Type approvals for gauges come from classification organisations like Lloyd’s Register, DNV, ABS, and Nippon Kaiji Kyokai (Class NK). They witness testing, review documentation, and certify compliance before issuing certificates.

This thorough approval process ensures that when a liquid level gauge is certified as SOLAS compliant (or carries the Wheelmark), shipbuilders and operators can trust its build quality, reliability, and reading accuracy. This commitment is essential for avoiding inspection failures, delays, or safety incidents at sea.

Seetru’s G31 Seeflex and G35 Seemag gauges are examples that satisfy these stringent SOLAS requirements and hold multiple type approvals, making them trusted choices for marine applications involving fuels and other hazardous liquids.

You can find more about our liquid level gauge approvals here.

A shipping vessel heavily loaded with colourful containers sails through blue waters, alongside SEETRU’s G31 liquid level gauge.

How Do You Know if Your Liquid Level Gauge is SOLAS Compliant?

The simplest way to check if your liquid level gauge is SOLAS compliant is to look for the type approval certificates issued by recognised classification organisations, like the ones mentioned earlier on. They are independent organisations that test and certify gauges to meet SOLAS safety standards.

Manufacturers like us usually provide copies of these certificates along with the product documentation or list their approved gauges on their websites.

For example, our G31 Seeflex and G35 Seemag gauges are widely recognised with SOLAS type approvals and certifications from multiple organisations. You can also look for marks or labels on the gauge itself indicating compliance. These may include certification symbols or serial numbers traceable to a testing report.

Lastly, when you’re looking to buy a liquid level gauge, always ask your supplier for proof of said certifications that prove the gauge is SOLAS compliant. This is especially important if you will be using the gauge on your ship or workboat to monitor flammable liquids. It also applies to other tanks that hold flammable or important liquids covered by SOLAS rules. This protects you from dealing with inspection failures and ensures compliance with international maritime law.

Final Thoughts…

By making sure your liquid level gauges meet IMO’s SOLAS rules, you help protect everyone on board your vessel. This reduces the chance of things going wrong at sea during your journey. These approvals show the equipment has passed strict safety tests and meets international maritime regulations.

Whether you work on cargo ships, offshore platforms, or luxury yachts, choosing a liquid level gauge that is SOLAS compliant where it needs to be helps you avoid inspection delays and safety risks. That’s why manufacturers like Seetru, offer various gauges certified by major classification organisations worldwide.

Keep in mind, rules can change a little for different ships and countries. So, to be sure your gauge is right for your vessel, always check the latest advice from your ship’s class society or ask a surveyor before you buy.


FAQ section for SOLAS compliant liquid level gauges

Does SOLAS apply to all tanks on board your vessel?

Not every single tank on board a vessel falls under SOLAS rules. SOLAS mainly focuses on safety, it applies to tanks that are linked to the ship’s operation, stability, and fuel systems. This means fuel tanks, ballast tanks, and other important service tanks are covered.
 
It’s not only big cargo ships and workboats that need to follow the rules. Luxury yachts like sailing yachts, and sport yachts, etc. They also come under SOLAS if they are over a certain size and/or carry passengers commercially. Whether you’re running a large commercial ship or a sleek private yacht. Your key tanks will need gauges that meet SOLAS requirements.

Do SOLAS compliant gauges need more maintenance?

No, not really. A liquid level gauge that is SOLAS compliant doesn’t mean extra work for you. The approval simply means the gauge has been tested to meet strict international safety rules. Once installed, the maintenance is about the same as with any other high-quality liquid level gauge.
 
What makes the difference is sticking to a proper inspection schedule. Regular checks keep gauges accurate and working as intended. If you already look after your equipment, adding a SOLAS compliant gauge won’t feel any different.

Are SOLAS rules the same for cargo ships and passenger ships?

The basic safety principles are the same, but some rules do change depending on the type of vessel. Cargo ships and passenger ships both need to follow the SOLAS framework, but passenger ships usually face stricter requirements. This is because they carry people rather than cargo, so the risk to life is higher.

For example, a large cruise ship must have more detailed safety systems in place than a bulk carrier.
But in both cases, the goal of SOLAS is the same:
to make sure the vessel is safe to run and that liquid level gauges and other equipment can be relied on in an emergency.