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Are you aware of the critical role pneumatic fenders play in ship safety? Choosing the right fender can prevent costly damage. ISO 17357 Pneumatic Fender standard ensures reliable protection during berthing and mooring.
This standard defines high-pressure and low-pressure fenders for various marine uses. It sets material, performance, and testing requirements to guarantee quality.
In this post, you’ll learn about ISO 17357’s scope, types of pneumatic fenders, and their applications in marine technology.
Table of Contents
ISO 17357-1:2014 defines high-pressure pneumatic fenders designed for ship berthing and mooring. These fenders operate at initial internal pressures of either 50 kPa or 80 kPa and are made from synthetic-tyre-cord reinforced rubber. Understanding their classification and types helps in selecting the right fender for specific marine applications.
There are three main types of high-pressure pneumatic fenders under ISO 17357:
Type I (Net-type): This fender features a protective net made from chain, wire, or fiber covering the body. It often includes used tires or rubber sleeves for extra protection. The net prevents damage from abrasion and enhances durability. The bead ring and cord turn-up construction at the flange may be omitted for this type to allow flexibility.
Type I Single: A variation of the Type I net-type, this fender has a flange opening only at one end. The opposite end lacks metal parts, which allows safe deformation if over-compressed. Installation usually places the no-metal end toward the expected impact zone to reduce damage risk.
Type II (Sling-type): This fender does not have a protective net. Instead, it uses lifting devices connected with guy chains or ropes at each end. The fender body itself acts as the contact surface. This type is preferred where net abrasion or entanglement could be problematic.
ISO 17357-1 specifies two pressure ratings for these pneumatic fenders:
Rating | Initial Internal Pressure | Typical Application |
|---|---|---|
Pneumatic 50 | 50 kPa | Standard use in most ship-to-ship (STS) and terminal operations |
Pneumatic 80 | 80 kPa | Higher energy absorption for confined berths and larger vessels |
Pneumatic 80 fenders absorb about 40% more energy than Pneumatic 50 fenders of the same size but also exert higher reaction forces on the vessel hull.
The fenders are constructed using synthetic-tyre-cord reinforced rubber. This reinforcement provides superior fatigue resistance and pressure retention compared to canvas fabric. The cords run primarily in one direction (warp), minimizing friction and wear during compression cycles. Canvas fabric, which has strength in both warp and weft directions, creates friction points that reduce durability and pressure holding. ISO 17357 explicitly prohibits canvas fabric for high-pressure pneumatic fenders.
Feature | Type I (Net-type) | Type II (Sling-type) |
|---|---|---|
Protection | Covered by chain, wire, or fiber net | No net; uses slings and lifting devices |
Metal Parts | Bead ring and flange present (may be omitted in some cases) | Bead ring and flanges present at both ends |
Contact Surface | Net and fender body | Fender body only |
Abrasion Resistance | High, due to protective net and sleeves | Moderate; vulnerable to abrasion without net |
Typical Applications | LNG terminals, STS transfers, offshore berths | Situations where net abrasion or entanglement is a concern |
Installation Considerations | Requires careful placement of no-metal end (Type I Single) | Sling attachments allow easy handling and positioning |
Choosing between Type I and Type II depends on operational conditions. Type I suits harsh environments needing extra protection, while Type II is ideal where nets could cause issues.
ISO 17357-1 sets clear material and construction standards to ensure high-pressure pneumatic fenders perform reliably in harsh marine environments. These requirements focus on the rubber compounds, reinforcement layers, bead rings, flange openings, and overall durability.
The outer and inner rubber layers of pneumatic fenders have distinct roles and must meet specific physical properties:
Outer Rubber: Protects against abrasion, ozone, and weather. It requires high tensile strength (≥18 MPa), elongation at break (≥400%), and tear strength (≥400 N/cm). Its hardness should be around 60 ± 10 Shore A. It must resist ozone cracking and maintain properties after aging tests (70°C for 96 hours). Compression set must be ≤30% to ensure shape recovery after compression.
Inner Rubber: Acts as an airtight liner sealing compressed air inside. It demands tensile strength ≥10 MPa and elongation ≥400%. Its hardness is slightly softer at 50 ± 10 Shore A. While it has fewer strict requirements than outer rubber, it must maintain integrity under pressure and aging.
Testing methods follow ISO standards such as ISO 37 for tensile strength, ISO 34-1 for tear strength, and ISO 1431-1 for ozone resistance. These tests confirm the rubber’s ability to withstand mechanical stress and environmental factors.
Reinforcement within the rubber layers is critical for pressure retention and fatigue resistance. ISO 17357-1 mandates synthetic-tyre-cord fabric for reinforcement, rejecting canvas fabric entirely.
Synthetic-Tyre-Cord: Has fibers aligned mainly in one direction (warp). This reduces friction between threads during repeated compression cycles, enhancing fatigue resistance and maintaining internal pressure longer.
Canvas Fabric: Has fibers woven in both warp and weft directions, creating friction points that lead to premature wear and pressure loss. ISO 17357 explicitly prohibits canvas fabric for high-pressure pneumatic fenders.
This distinction ensures the fender can endure thousands of compression cycles without failure.
Bead rings are steel rings fitted at one or both fender ends. They anchor the cord layers and help maintain structural integrity. ISO 17357 limits bead ring diameter to less than 20% of the fender diameter (0.20D) to prevent deformation during over-compression.
Flange openings are steel flanges mounted on the fender to attach air valves or safety valves. These openings must be robust to maintain airtightness and allow easy maintenance or pressure adjustments.
For Type I (net-type) fenders, bead rings and flange openings may be omitted at one end (Type I Single) to allow safe deformation under extreme compression.
Durability is vital for fenders exposed to constant impact, UV, saltwater, and temperature changes. The outer rubber’s abrasion resistance protects the fender from physical damage. The protective netting on Type I fenders further enhances durability by shielding the rubber from direct contact damage.
The synthetic-tyre-cord reinforcement supports pressure retention and prevents structural failures. Combined with proper bead ring and flange design, these elements ensure the fender withstands repeated loading cycles without permanent deformation or air leakage.
ISO 17357-1 sets strict performance criteria and testing methods to ensure high-pressure pneumatic fenders meet safety and durability requirements during ship berthing and mooring. These tests confirm the fender's ability to absorb energy, withstand repeated compression, and maintain airtightness.
Two key performance parameters define pneumatic fender effectiveness:
Guaranteed Energy Absorption (GEA): The amount of energy the fender can absorb without permanent damage or deformation. ISO 17357-1 rates GEA at a deflection of 60 ± 5% of the fender’s diameter. The fender must absorb at least 100% of its rated energy below 65% deflection.
Reaction Force (RF): The force the fender exerts back on the vessel hull at rated deflection. It must remain within ±10% of the rated value to avoid excessive hull stress or insufficient resistance.
Together, GEA and RF ensure the fender cushions impacts effectively without damaging the ship or fender.
Prototype tests validate the design before production. They include:
Parallel Compression Test: The fender undergoes two cycles of compression along its axis at a slow rate until reaching the GEA deflection. Results average both cycles. This confirms energy absorption and reaction force meet specifications.
Angular Compression Test: The fender is compressed at an angle to simulate real berthing scenarios. This tests deformation characteristics under off-center impacts.
Durability Test: The fender is compressed repeatedly (minimum 3,000 cycles) to check for cracks, air leaks, or loss of performance. No permanent damage or GEA reduction is allowed.
Puncture Resistance Test: Using a CBR (California Bearing Ratio) test, the fender must resist puncture forces exceeding 15 kN, ensuring protection from sharp objects.
Compression Recovery Test: After holding compression at GEA for one minute, the fender must recover at least 97% of its original diameter within five minutes, demonstrating good elastic recovery.
Prototype certificates are valid for 10 years and must be evaluated by a major classification society.
Each production batch undergoes acceptance tests:
Test Type | Scope | Frequency |
|---|---|---|
Rubber Material Tests | Hardness every lot; tensile, elongation, tear, compression set, ozone annually | Hardness: every lot; others: yearly |
Dimensional Inspection | Diameter and length at initial pressure | Every fender |
Air-Leakage Test | No leaks over 30 minutes at initial pressure | Every fender |
Hydrostatic Pressure Test | No leaks under rated test pressure for 10 minutes | 1 per 20 fenders |
Dimensional tolerances allow +10% to −5% variation in diameter and length.
The fender must recover elastically after compression. After a 1-minute hold at GEA deflection, it should regain at least 97% of original diameter within 5 minutes. This prevents permanent deformation and ensures long service life.
ISO 17357-1 sets clear guidelines for inspection and quality assurance to ensure pneumatic fenders meet performance and safety standards. These processes involve third-party independent inspection, detailed documentation, regular inspections during production, and benefits especially important for critical applications like LNG terminals and offshore facilities.
Third-party inspection is a key part of quality assurance but is not automatically required. Buyers must specify it in procurement documents to make it mandatory. Independent inspections are usually performed by major classification societies such as Bureau Veritas (BV), DNV, ABS, or Lloyd’s Register.
These inspections verify:
Compliance of synthetic-tyre-cord materials with certificates
Rubber compound test results
Dimensional measurements of each fender
Air-leakage tests ensuring airtightness
Hydrostatic-pressure tests confirming structural integrity
Proper marking and documentation
Inspectors witness critical tests and confirm results, providing unbiased validation. This independent oversight reduces risk of substandard fenders entering service.
ISO 17357 requires manufacturers to provide clear documentation and marking for each fender. Marking includes:
Manufacturer’s name or trademark
Production date
Fender type and size
Initial internal pressure rating
Serial or batch number for traceability
Documentation includes test reports covering prototype performance tests, commercial batch tests, and material certificates. This traceability ensures accountability and helps track fender history throughout its service life.
Inspections occur at multiple stages:
Prototype Testing: One-time full-scale testing of a new design includes compression, durability, puncture resistance, and recovery tests. Valid for 10 years.
Commercial Testing: Every production batch undergoes material hardness tests, dimensional checks, air-leakage tests, and periodic hydrostatic-pressure tests.
Third-Party Inspection: If specified, inspectors verify commercial test results and witness pressure tests for each batch or lot.
This layered inspection approach ensures consistent quality from design to delivery.
LNG terminals and offshore projects demand the highest safety and reliability. Third-party inspection offers:
Enhanced confidence in fender performance and durability
Reduced risk of operational failures and costly downtime
Compliance with international regulations and industry best practices
Support for insurance and certification requirements
Independent inspection helps avoid ambiguity in quality expectations and fosters trust between buyers, manufacturers, and end-users.
When buying pneumatic fenders, clear and precise specifications ensure the delivered product meets your needs and complies with ISO 17357-1:2014. Avoid ambiguity by including key details about the standard, fender size, type, pressure rating, and inspection requirements.
Specify the following in your procurement documents:
Standard number and version: Always state "ISO 17357-1:2014" to confirm high-pressure pneumatic fenders.
Fender size: Diameter × length, chosen from the standard’s size tables or custom sizes per Clause 6.3.3.
Fender type: Type I (net-type), Type I Single, or Type II (sling-type).
Initial internal pressure: Either 50 kPa (Pneumatic 50) or 80 kPa (Pneumatic 80).
Fender color: Usually black unless otherwise specified.
Including these details avoids confusion over the product’s design and performance parameters.
Safety valves: Mandatory for fenders with diameters ≥2,500 mm. For smaller sizes, specify if a valve is required.
Identification system: Request embedded serial numbers or markings for traceability purposes.
These features enhance safety and help track fender history throughout its service life.
ISO 17357-1 allows but does not require third-party inspection. To guarantee independent quality verification, explicitly state:
Third-party inspection requirement: Reference Clause 12 and name the inspection authority (e.g., Bureau Veritas, DNV, ABS, Lloyd’s Register).
Manufacturer certification: Require prototype test certificates (Clause 8), commercial batch test reports (Clause 9), and material certificates for synthetic-tyre-cord reinforcement.
This ensures the fender meets all performance and material standards, reducing risk of substandard products.
Common pitfalls include vague references such as "ISO 17357 fender" without specifying part number, type, or inspection clauses. This leads to mismatched expectations and potential disputes.
To prevent this:
Use full standard references: "ISO 17357-1:2014"
Specify all critical parameters (size, type, pressure)
Clearly state inspection and certification requirements
Avoid brand names alone (e.g., "Yokohama") without referencing the governing standard
A well-drafted procurement clause example:
"Fenders shall comply with ISO 17357-1:2014. Size: 3,300 × 6,500 mm, Type II (sling-type), Pneumatic 50. Safety valve required as per Clause 6.1.7. Third-party inspection per Clause 12 by Bureau Veritas is mandatory. Manufacturer to provide prototype test certificate per Clause 8, commercial test reports per Clause 9, and material certificates for synthetic tyre cord."
This level of detail ensures clarity, compliance, and quality assurance.
ISO 17357 is split into two parts, each covering different pneumatic fender types:
Part 1 (ISO 17357-1:2014): Applies to high-pressure pneumatic fenders inflated to either 50 kPa or 80 kPa. These fenders are made from synthetic-tyre-cord reinforced rubber. They are designed for demanding applications such as LNG terminals, ship-to-ship (STS) transfers, and offshore single point moorings (SPM).
Part 2 (ISO 17357-2:2014): Covers low-pressure pneumatic fenders inflated to about 7 kPa. These use vulcanized-rubber-coated textile rather than reinforced rubber. They are typically used for harbor berthing and smaller vessels.
The key distinction lies in pressure rating and construction material. Part 1 fenders handle higher loads and absorb more energy, while Part 2 fenders suit lighter-duty applications.
Under ISO 17357-1, two main types exist:
Type I (Net-type): Features a protective net made from chain, wire, or fiber covering the fender body. It often includes used tires or rubber sleeves for extra abrasion resistance. This type is common in harsh environments like LNG terminals and STS operations.
Type II (Sling-type): Has no protective net but uses slings and lifting devices at each end. The fender body itself contacts the vessel hull. This type is preferred where nets risk abrasion, entanglement, or complicate handling.
Both types meet the same performance criteria. The choice depends on operational needs: Type I offers extra protection; Type II favors ease of handling and reduced abrasion risk from nets.
ISO 17357-1 includes Clause 12, which defines third-party independent inspection by classification societies such as Bureau Veritas, DNV, ABS, or Lloyd’s Register. However, this inspection is not mandatory by default.
Buyers must explicitly require third-party inspection in procurement documents to make it compulsory.
For critical applications like LNG terminals, FSRU projects, and STS transfers, third-party inspection is standard practice.
This inspection covers material certification, dimensional checks, air-leakage tests, hydrostatic-pressure tests, and marking verification.
It provides unbiased verification of compliance and helps ensure safety and reliability.
Without such a clause, only manufacturer batch testing per Clause 9 is performed, which lacks independent oversight.
Prototype tests validate the fender design before production. The resulting test certificate:
Is valid for 10 years from the test date.
Must be evaluated and approved by a major classification society.
Covers full-scale performance tests including compression, durability, puncture resistance, and recovery.
After 10 years, the manufacturer must repeat the prototype tests to maintain certification.
Fenders smaller than the prototype (with fewer reinforcement plies but the same design) do not require separate prototype testing.
Adhering to ISO 17357 ensures pneumatic fenders deliver reliable performance and safety in marine berthing. This standard covers fender types, materials, testing, and quality assurance. Compliance improves durability and reduces operational risks. Following these guidelines guarantees longer service life and effective energy absorption. Future updates will enhance fender technology and standards. www.hongruntongfender.com Hongruntong Marine (Beijing) Co., Ltd. offers high-quality pneumatic fenders designed to meet ISO 17357, providing durable, safe solutions for demanding marine environments.
A: An ISO 17357 Pneumatic Fender is a high-pressure marine fender made from synthetic-tyre-cord reinforced rubber, designed for ship berthing and mooring with internal pressures of 50 or 80 kPa.
A: Type I fenders have protective nets for abrasion resistance, while Type II use slings without nets, preferred where net abrasion or entanglement is a concern.
A: They offer superior energy absorption, durability, and compliance with strict testing for safe ship impact cushioning.
A: Cost depends on size, type (I or II), pressure rating (50 or 80 kPa), and additional features like third-party inspection.
A: Inspect bead rings, flange openings, and rubber integrity; ensure proper maintenance and verify compliance with ISO 17357 sealing standards.
