Inspection Encyclopedia | Life Jacket Inspection and Testing

Life jackets, as a crucial piece of personal protective equipment (PPE), have the core function of ensuring a person remains afloat after falling into the water. Their design and production must strictly adhere to internationally accepted technical specifications as well as specific national regulations. The mainstream types currently on the market include foam life jackets that rely on inherent buoyancy and inflatable life jackets that generate buoyancy through an inflatable device. To ensure safety and reliability, a standardized inspection system for life jackets is crucial, especially for inflatable life jackets, whose more complex structures require an especially meticulous and comprehensive inspection process.

Overview of Life Jacket Inspection Standards

1. Inspection standards for inflatable life jackets

   • Export to EU countries: Life jackets must be CE certified (or comply with the corresponding ISO standards). Certification levels are strictly divided into three levels based on the minimum buoyancy (in Newtons) that the life jacket can provide:

     • 100N level: Suitable for sheltered calm waters or near-shore coastal navigation environments, providing basic buoyancy.

     • 150N level: Suitable for offshore (coastal) navigation, providing a higher level of buoyancy support.

     • 275N level: Designed specifically for deep-sea navigation and extremely harsh sea conditions, it provides the highest level of buoyancy to ensure the survival of personnel in the most dangerous conditions.

   • Export to the United States: The relevant standards are developed and supervised by the United States Coast Guard (USCG). The classification is also mainly based on the minimum buoyancy, which corresponds to the European standards:

     • Level I: This level is the highest performance level, and the inflatable life jacket must provide 150N of buoyancy (foam type is 100N). It is suitable for all types of ships, including the most challenging sea conditions.

     • Level II: This level is suitable for lower-risk waters. The inflatable life jacket must provide 100N of buoyancy (70N for a foam type). It is primarily designed for sailing in calm waters such as inland lakes and rivers.

2. National Testing Standards for Life Jackets (China)
   China has developed a series of detailed national standards (GB/T and GB) for different types of life jackets, which are the fundamental basis for domestic production, sales and export inspections. They mainly include:

   • GB/T 4303-2008 Marine Life Jackets: specifies the basic requirements for general marine life jackets.

   • GB/T 5869-2010 "Life Jacket Lights": specifically stipulates the technical standards for the position-indicating lights equipped with life jackets.

   • GB/T 32227-2015 Marine Work Lifejackets: Special requirements for crew members wearing lifejackets for daily work.

   • GB/T 32232-2015 Children's Life Jackets: A standard for life jackets designed specifically for children's body shape and safety needs.

   • GB/T 36508-2018 "Inflatable Life Jackets for Aviation": Standardizes inflatable life jackets used in the aviation field.

   • GB 41731-2022 Marine Inflatable Life Jackets: This is the latest mandatory national standard , which was issued on July 13, 2022 and officially implemented on February 1, 2023. It puts forward comprehensive and mandatory technical requirements for marine inflatable life jackets.
     Core Principles: Regardless of the export destination, life jacket products must strictly comply with the current regulations and standards of the target sales country/region and the requirements of specific application scenarios (such as ship type and navigation area).

GB 41731-2022 Detailed Explanation of Key Inspection Requirements for Marine Inflatable Life Jackets

1. Appearance and design inspection requirements for marine inflatable life jackets

1. Color requirements: The main body color of the life jacket must be highly visible orange-red or orange-yellow, or other bright colors that are easily identified in the marine environment to facilitate search and rescue.

2. Convenience of wearing: Life jackets should be designed to be worn on both sides, ensuring quick and correct donning in an emergency. If a life jacket is designed to be worn only on one side, this indication must be clearly marked in a prominent location on the life jacket.

3. Lashing system: It must be equipped with a quick, simple and reliable closing and fastening device so that the wearer can quickly and accurately fasten the life jacket to the body without performing complicated knotting operations.

4. Applicability identification: The height and weight ranges for the wearer specified in the table below must be clearly marked on a conspicuous part of the life jacket. Life jackets specifically for children must also be marked with a prominent "Children's Life Jacket" logo.

5. Retroreflective tape: When the wearer is in a static equilibrium floating state in the water, the total area of retroreflective material attached to the outer surface of the life jacket that is above the water surface shall not be less than 400 square centimeters. The reflective tape must fully comply with the performance standards specified in IMO Resolution MSC.481(102).

6. Adaptability to large number of people: If not specifically designed for persons weighing more than 140 kg or with a chest circumference greater than 1750 mm, adult lifejackets must be equipped with suitable accessories (such as extension belts) to ensure that such persons can also effectively fasten and wear them.

7. Throwable buoyant line: The life jacket should be designed with a throwable buoyant lifeline (or other equivalent means) to be used to connect to another person in distress in the water during rescue.

8. Lifting device: An effective lifting device or attachment (such as shoulder straps or lifting rings) must be provided to facilitate rescuers to lift the wearer from the water into a survival craft or rescue boat.

9. Life jacket light fixing: Life jackets must be designed with stable and reliable life jacket light mounting and fixing equipment to ensure that the light can be firmly attached and function normally in harsh environments.

10. Buoyancy chamber design:

    • Must rely on inflatable air chambers as the main source of buoyancy.

    • There should be at least two independent closed air chambers.

    • The inflation or leakage of any air chamber shall not affect the integrity and buoyancy of other air chambers.

    • After being immersed in water, it should be ensured that no less than two air chambers can be automatically triggered to inflate.

    • A manual inflation trigger device (pull cord/ring) must be provided.

    • It must be possible to supplement the inflation of each air chamber by blowing air by mouth.

11. Single chamber failure redundancy: In the extreme case that any independent air chamber completely loses buoyancy (failure), the remaining buoyancy system should still be able to continue to meet the performance requirements (such as buoyancy, stability, etc.) specified in the standard to ensure the basic safety of the wearer.

II. Material performance test requirements for marine inflatable life jackets

1. Inflatable Air Chamber Coated Fabric:

   • Coating Adhesion: Whether in a dry or wet state, the average adhesion between the coating and the base fabric shall not be less than 50 Newtons/50 mm width (the test method must be in accordance with the standard).

   • Tear strength: The average tear strength of the material must be ≥35 Newtons to resist external tearing damage.

   • Breaking strength and elongation: In both dry and wet states, the material’s average breaking strength must be ≥200 Newtons; at the same time, the average elongation at break must be ≤60% to ensure that the material is strong and not over-stretched.

   • Flex crack resistance: After the repeated bending and flexure test specified in the standard, there shall be no visible cracks or physical damage on the material surface and coating.

   • Color fastness:

     • Abrasion resistance (wet/dry): The color fastness levels for both dry and wet rubbing must be ≥ level 3 (assessed according to the grayscale card) to prevent color migration.

     • Light resistance: The resistance to light fading must be ≥ level 5 to ensure color stability under long-term exposure to sunlight.

     • Seawater resistance: The color retention ability after immersion in seawater must be ≥ level 4 to prevent discoloration caused by seawater corrosion.

2. Strap (webbing):

   • Standard breaking strength: The average breaking strength of the strap under normal conditions must be ≥1600 Newtons.

   • Breaking strength after aging: After accelerated testing simulating environmental aging, the average breaking strength of the strap must still be ≥1600 Newtons and must not be less than 60% of its standard breaking strength.

3. Buckles (buckles, D-rings, etc.):

   • Standard breaking strength: The average breaking strength of the buckle under normal conditions must be ≥1600 Newtons.

   • Breaking strength after aging: After accelerated testing simulating environmental aging, the average breaking strength of the fastener must still be ≥1600 Newtons and must not be less than 60% of its standard breaking strength.

   • Breaking strength after salt spray: After the salt spray corrosion test specified by the standard, the average breaking strength of the fastener must still be ≥1600 Newtons and must not be lower than 60% of its standard breaking strength to ensure its mechanical reliability in the marine corrosion environment.

3. Other comprehensive performance test requirements for marine inflatable life jackets

1. Whistle:

   • Functionality and sound pressure: The whistle of a life jacket must be able to produce a clear and loud whistle immediately after being immersed in fresh water and removed. Its sound pressure level must reach above 100 decibels (A-weighted) to ensure that the call for help can be heard from a distance.

   • Material and design: The main material of the whistle should be non-metallic (such as plastic), with a smooth surface and no burrs to prevent cuts, and it should be designed to produce sound independently without the help of other objects (only by blowing air from the mouth).

   • Securing and Position: The whistle must be securely fastened to the life jacket with a thin rope. Its installation position must not hinder the normal function or wearing comfort of the life jacket, and ensure that the wearer can easily access and blow it with both hands.

   • Lanyard strength: The strength of the thin rope connecting the whistle must meet the specific tensile requirements of Article 52 of the GB/T 322348-2015 standard.

2. Temperature cycle adaptability: Lifejacket samples must undergo 10 cycles of alternating high-temperature (+65°C?) and low-temperature (-30°C?) impact tests. Upon completion, the lifejacket and its components (including air chambers, valves, and materials) must show no signs of damage, such as shrinkage, rupture, abnormal expansion, material decomposition, or mechanical degradation.

3. Inflation performance reliability:

   • After each high and low temperature cycle test, the life jacket's automatic inflation system and manual inflation system must be tested immediately. Both must be able to start normally and fill the life jacket with sufficient gas.

   • After the life jacket is stored in a high temperature environment of +40℃ and a low temperature environment of -15℃ for 8 hours respectively, its manual inflation system must still be able to operate effectively and fill the air chamber with air.

4. Buoyancy loss rate: After a fully inflated life jacket is completely immersed in fresh water for 24 hours, the loss of its overall buoyancy shall not exceed 5% of the initial buoyancy, ensuring that it still has sufficient buoyancy after long-term immersion.

5. Flame retardant properties: The life jacket material should be removed after being exposed to flames for 2 seconds. The material itself should not continue to burn for more than 6 seconds after the flame leaves, and no continuous melting dripping should occur to reduce the risk of fire.

6. Structural strength:

   • Body and handles: The main structure and lifting ring (device) of the life jacket must be able to withstand a static load of 3200 Newtons for 30 minutes without damage (the requirement for children's life jackets is 2400 Newtons).

   • Shoulder strength: The shoulder area of the life jacket must be able to withstand a static load of 900 Newtons for 30 minutes without damage (700 Newtons for children's life jackets) to ensure reliability during lifting and rescue.

7. Wearing performance test:

   • Without any instructions, at least 75% of the testers can put on the life jacket independently and correctly within 1 minute.

   • After simple instructions on how to put it on, 100% of the testers must complete the wearing process correctly within 1 minute.

   • When the testers simulated wearing thicker winter clothes (bulky clothing), 100% of the testers were required to put on the life jackets correctly within 1 minute.

   • The above tests must be carried out with the life jacket in both the uninflated and inflated states to assess operability in different states.

8. Water performance (core safety indicators):

   • Righting ability (turned face up): The average time required for a person who falls into the water to turn from face down to a safe face up position while wearing the tested lifejacket shall not exceed the average turning time when wearing a standard adult reference lifejacket (RTD, which must comply with IMO MSC.1/Circ.1470) plus 1 second. If a person is unable to turn (face down) during a test, the number of such turns shall not exceed the number of turns when wearing an RTD.

   • Static balance posture: When the wearer is floating face up in water:

     • a) Net height (height of mouth and nose from water): The average net height of all test subjects should be ≥ the average net height when wearing RTD minus 10 mm.

     • b) Torso angle (backward angle): The average torso angle of all test subjects should be ≥ the average torso angle when wearing the RTD minus 10°.

   • Diving and falling into water: After the tester wears a life jacket (usually in an uninflated or cocked state) and performs a simulated fall into water or active diving test, the following conditions must be met:

     • a) The person who falls into the water can be quickly kept in a face-up position, and the average net height of the mouth and nose of all test subjects above the water is ≥ the average net height when wearing RTD measured according to the standard procedure minus 15 mm.

     • b) The life jacket does not shift or fall off, and does not cause any physical harm to the wearer.

     • c) The air chamber is not damaged due to impact, which would affect the underwater performance or buoyancy.

     • d) The life jacket light is not detached or damaged.

   • Stability (anti-sway): After the test subject enters the water, the life jacket should not swing excessively from side to side, causing the test subject's mouth and nose to be submerged in the water. The number of test subjects who can automatically return to a stable face-up, fetal position while wearing the tested life jacket should be at least the same as the number who can achieve this position while wearing an RTD.

   • Swimming and rafting ability: After swimming 25 metres while wearing the lifejacket being tested, the proportion of test subjects who are able to successfully climb onto a liferaft or onto a rigid platform 300 mm above the water surface should be not less than two-thirds of the number of people who succeeded when performing the same test without wearing a lifejacket.

9. Inflatable head (valve) load tolerance: After applying a force of (220±10) Newtons from all directions to the inflation valve (inflation head) of the life jacket, the valve itself must not be damaged. The entire life jacket system must remain airtight after this test, with no leakage within 30 minutes.

10. Pressure resistance (non-inflated state): When a life jacket is in a normal storage state (not inflated), after being subjected to a static load of 75 kg (simulated heap pressure), the life jacket body should not expand abnormally or have its mechanical properties changed, and the internal air chamber should not leak.

11. Pressure performance (inflated):

    • Overvoltage tolerance: At room temperature, the life jacket chamber should be able to withstand excessive pressure applied internally (specific values according to the standard) and remain structurally intact under this pressure for 30 minutes.

    • Release valve function (if equipped): If a lifejacket is equipped with an overpressure relief valve, the valve must be able to effectively release excess gas when the pressure exceeds the set safety value. The lifejacket must remain structurally intact and maintain the residual pressure for 30 minutes after pressure relief. It must not show signs of damage such as rupture, abnormal expansion, or changes in mechanical properties, and the function of the inflatable components should not be significantly affected.

    • Air retention: When the life jacket chamber is filled with air (not CO2), and left to stand at room temperature for 12 hours, the pressure drop in the chamber shall not exceed 10% of the initial pressure.

12. Requirements for metal parts:

    • Corrosion resistance: All metal parts and components used in lifejackets must have excellent seawater corrosion resistance. After completing the salt spray test in accordance with the standard, the metal parts should not show obvious corrosion, and the corrosion products must not affect other parts of the lifejacket (such as contaminating or cutting the fabric), and the overall performance of the lifejacket must not be reduced.

    • Magnetic compass influence: When the metal parts on the life jacket are placed 500 mm away from the standard magnetic compass, the interference deviation angle caused by the metal parts on the magnetic compass reading shall not exceed 5° to avoid affecting the ship's navigation.

13. Preventing mis-inflation mechanism: Life jackets must be designed with reliable safety devices (such as locking pins, pull ring protection covers, etc.) that can effectively prevent unexpected and dangerous inflation due to accidental touch, hooking, etc. during daily transportation, storage or wearing.