Stainless Steel Forged High Pressure Sample Cylinders Explained: Key Specifications, Features, and Common Uses

Types of Stainless Steel Forged High Pressure Sample Cylinders

Stainless steel forged high-pressure sample cylinders are engineered for demanding environments where reliability, durability, and sample integrity are critical. These cylinders are manufactured using precision forging techniques that enhance strength, eliminate porosity, and ensure resistance to extreme pressures and corrosive substances. Available in several specialized series, each type is tailored to meet the unique requirements of industries ranging from pharmaceuticals to aerospace. Choosing the right cylinder ensures safe, contamination-free storage and transport of sensitive samples under high-pressure conditions.

SCA-HP Series

Designed for extreme high-pressure applications, the SCA-HP series features cylinders forged from premium-grade stainless steel, offering exceptional tensile strength and corrosion resistance. These cylinders are ideal for preserving sample integrity in harsh environments.

Advantages

• High tensile strength for extreme pressure tolerance
• Superior corrosion resistance in aggressive chemical environments
• Forged construction eliminates weak points and weld seams
• Ensures long-term reliability and minimal maintenance

Considerations

• Heavier than some lightweight alternatives
• Higher cost due to precision forging process

Best for: Oil & gas exploration, chemical processing, environmental monitoring, and high-pressure field sampling

STC Series

The STC series combines a lightweight forged stainless steel body with robust structural integrity, making it ideal for portable high-pressure applications. With capacities ranging from 0.5L to 2.0L, these cylinders offer versatility without compromising safety.

Advantages

• Lightweight yet durable forged design
• Wide capacity range for flexible use
• Resistant to thermal and mechanical stress
• Ideal for mobile and field-based operations

Considerations

• Not recommended for ultra-high-pressure systems beyond rated limits
• May require protective casing in rugged environments

Best for: Aerospace testing, medical gas storage, portable fluid sampling, and laboratory fieldwork

SFC Series

Engineered for scientific precision, the SFC series delivers unmatched consistency and durability in high-pressure sample containment. These cylinders are optimized for applications where repeatability and purity are paramount.

Advantages

• Precision-engineered for uniform pressure distribution
• Excellent resistance to fatigue under cyclic loading
• Maintains sample purity with inert stainless steel surface
• Designed for integration with analytical instrumentation

Considerations

• Requires careful handling to avoid surface contamination
• Higher initial investment for research-grade applications

Best for: Research laboratories, academic institutions, quality control testing, and advanced material analysis

HPC Series

The HPC (High-Purity Cylinder) series is built for industries where contamination control is non-negotiable. These leak-proof, forged stainless steel cylinders ensure the highest level of chemical stability and sample protection.

Advantages

• Leak-tight design for maximum safety
• Exceptional chemical compatibility with reactive substances
• Smooth internal finish minimizes residue retention
• Certified for pharmaceutical and biotech compliance standards

Considerations

• Requires strict cleaning protocols between uses
• Premium pricing reflects high-purity engineering

Best for: Pharmaceutical manufacturing, biotechnology, semiconductor gas delivery, and sterile sampling environments

Expert Tip: Always verify the pressure rating and material compatibility of your cylinder with the specific media being stored. For high-purity applications, implement a documented cleaning and certification process to maintain compliance with industry standards such as USP <87> or ISO 11114.

Industrial Applications of Stainless Steel Forged High-Pressure Sample Cylinders

Stainless steel forged high-pressure sample cylinders are essential tools across multiple high-stakes industries, where the safe, reliable, and contamination-free handling of volatile or sensitive samples is critical. Engineered for durability, corrosion resistance, and performance under extreme pressure and temperature conditions, these cylinders ensure sample integrity from collection to analysis. Below is a detailed overview of their key industrial applications, highlighting their specialized variants and operational benefits.

1. Oil and Gas Industry

Function: High-pressure sample cylinders are used to extract, transport, and store crude oil, natural gas, and drilling fluids from remote well sites, offshore platforms, and refineries. These samples are analyzed to determine composition, purity, sulfur content, and other critical parameters for quality control and regulatory compliance.

Performance Requirements: The oil and gas sector operates in environments with extreme pressures (up to 15,000 psi) and temperatures ranging from sub-zero to over 200°C. The SCA-HP series cylinders are specifically engineered to withstand these harsh conditions, featuring seamless forged stainless steel construction that resists cracking, pitting, and hydrogen embrittlement.

Key Benefits: Leak-proof sealing, long-term stability, and compatibility with sour gas (H₂S) environments make these cylinders indispensable for upstream, midstream, and downstream operations.

2. Chemical Processing

Function: In chemical manufacturing and R&D facilities, sample cylinders safely contain reactive, corrosive, or toxic substances such as solvents, acids, alkalis, and intermediate compounds. These materials must be transported without degradation or risk of leakage during process monitoring and quality assurance testing.

Performance Requirements: Exposure to aggressive chemicals demands materials with superior corrosion resistance. The FT series cylinders, made from forged 316L stainless steel, offer exceptional resistance to chlorides, oxidizing agents, and organic solvents. Their smooth internal finish minimizes residue buildup and facilitates cleaning.

Key Benefits: Enhanced safety, reduced contamination risk, and compliance with OSHA and EPA standards for hazardous material handling. Ideal for batch process validation and reactor sampling.

3. Aerospace Engineering

Function: In aerospace applications, sample cylinders are used to test fuel formulations, hydraulic fluids, lubricants, and gaseous propellants under simulated flight conditions. These tests ensure material performance at high altitudes, extreme temperatures, and rapid pressure changes.

Performance Requirements: Components must be lightweight yet robust enough to endure cyclic stress and thermal shock. The SC series cylinders are optimized for aerospace use with a high strength-to-weight ratio, excellent fatigue resistance, and certification for use in vacuum and cryogenic environments.

Key Benefits: Precision engineering ensures consistent sample integrity during ground testing and in-flight monitoring. Suitable for use in jet engine development, spacecraft life support systems, and environmental control testing.

4. Environmental Monitoring

Function: Environmental agencies and research institutions rely on high-pressure sample cylinders to collect air, water, and soil gas samples from polluted sites, industrial zones, and remote ecosystems. These samples are analyzed for pollutants such as VOCs (volatile organic compounds), greenhouse gases, and heavy metals.

Performance Requirements: Long-term field deployment requires resistance to moisture, salt spray, and biological fouling. The SFC series cylinders feature enhanced corrosion protection and inert internal surfaces that prevent adsorption or reaction with trace analytes.

Key Benefits: Reliable data collection for regulatory reporting, climate studies, and pollution tracking. Ideal for use in marine environments, urban air quality networks, and groundwater monitoring wells.

5. Pharmaceutical Industry

Function: In pharmaceutical manufacturing, maintaining sample purity is non-negotiable. Forged stainless steel cylinders are used to store and transport high-pressure samples of active pharmaceutical ingredients (APIs), solvents, and final drug products during process validation, stability testing, and quality control.

Performance Requirements: The cylinders must be non-reactive, easy to sterilize, and compliant with cGMP (current Good Manufacturing Practices) and FDA guidelines. Their seamless construction prevents microbial ingress and cross-contamination.

Key Benefits: Ensures sample integrity throughout the drug development lifecycle. The ultra-clean finish and traceability features (e.g., laser-etched serial numbers) support audit readiness and regulatory compliance.

Important: Always ensure that high-pressure sample cylinders are inspected, tested, and certified according to ASME, DOT, or PED standards before use. Improper handling, over-pressurization, or use of incompatible materials can lead to catastrophic failure. Regular hydrostatic testing and valve maintenance are essential for operational safety and regulatory compliance.

Product Specifications and Features of Stainless Steel Forged High-Pressure Sample Cylinders

Stainless steel forged high-pressure sample cylinders are essential components in industries requiring secure, reliable containment of sensitive samples under extreme conditions. Engineered for durability, safety, and chemical inertness, these cylinders are widely used in petrochemical, aerospace, pharmaceutical, and environmental testing applications. Below is a comprehensive overview of their technical specifications, installation procedures, and maintenance best practices.

Technical Specifications

Material Composition

These high-pressure cylinders are precision-forged from premium-grade stainless steel alloys, primarily 316L and 304L, chosen for their exceptional strength-to-weight ratio and corrosion resistance.

• 316L Stainless Steel: Contains molybdenum (2–3%), significantly enhancing resistance to chloride-induced pitting and stress corrosion cracking—ideal for marine, chemical processing, and offshore environments.
• 304L Stainless Steel: Offers excellent general corrosion resistance and weldability, making it suitable for most ambient and industrial conditions where chloride exposure is minimal.
• Low carbon content (≤0.03%) in both alloys prevents carbide precipitation during welding, preserving structural integrity.

Key Advantage: Forged construction eliminates seams and weak points, providing superior strength compared to welded or machined alternatives.

Cylinder Volume & Capacity

Available in a range of internal volumes from 0.5 liters to 5 liters, these cylinders are designed to accommodate diverse sampling needs—from laboratory-scale analysis to field testing and process monitoring.

• Smaller volumes (0.5–1L) are ideal for gas chromatography, environmental air sampling, and calibration standards.
• Larger capacities (2–5L) support bulk liquid or gas storage in industrial R&D and quality control settings.
• All volumes maintain consistent wall thickness and pressure ratings due to uniform forging processes.

Design Note: Internal surface finishes are electropolished to reduce sample adhesion and prevent contamination.

Maximum Pressure Rating

Rated to withstand pressures up to 6,000 psi (414 bar), these cylinders ensure safe containment of volatile gases, liquefied samples, and reactive substances without deformation or leakage.

• Meets or exceeds ASME, DOT, and ISO standards for high-pressure vessel integrity.
• Commonly used in natural gas sampling, hydrogen storage, and supercritical fluid extraction.
• Tested at 1.5x working pressure during manufacturing for safety compliance.

Critical Application: Essential in upstream oil & gas operations where downhole fluid samples must remain pressurized during transport to surface labs.

Temperature Resistance

Engineered to operate reliably across an extended temperature range of -196°C to +200°C (-320°F to +392°F), enabling use in both cryogenic and elevated-temperature environments.

• Compatible with liquid nitrogen storage and transport (LN2 at -196°C).
• Stable performance in high-heat industrial reactors and thermal cycling tests.
• Thermal expansion coefficients of stainless steel minimize stress during rapid temperature shifts.

Safety Tip: Avoid thermal shock by gradually bringing cylinders to operating temperatures.

Safety Features

Equipped with integrated safety mechanisms to prevent catastrophic failures under overpressure or extreme conditions.

• Burst Discs: Precision-calibrated rupture discs release excess pressure at a predetermined threshold, protecting personnel and equipment.
• Pressure Relief Valves: Automatically vent gas if internal pressure exceeds safe limits; often temperature-activated as a secondary safeguard.
• Double-Seal Valves: Minimize leakage risk with redundant sealing surfaces on cylinder valves.
• Protective Caps: Shield valve stems from impact damage during handling and transport.

Regulatory Compliance: Designed in accordance with OSHA, CGA, and PED directives for hazardous material containment.

Installation Guidelines

Proper installation is critical to maintaining sample integrity, ensuring operator safety, and prolonging cylinder lifespan. Always follow manufacturer instructions and site-specific safety protocols.

Preparation

Before installation, conduct a thorough assessment of the work environment to eliminate potential hazards.

• Clear the area of flammable materials, electrical hazards, and tripping risks.
• Verify that the workspace is clean, dry, and free from dust, moisture, and chemical contaminants.
• Inspect the cylinder for visible damage, dents, or corrosion—do not install if any defects are present.
• Confirm compatibility between the cylinder valve outlet and the receiving system (e.g., CGA connections).

Best Practice: Use personal protective equipment (PPE) including gloves, face shield, and safety goggles during setup.

Mounting the Cylinder

Secure mounting prevents accidental tipping, vibration, or mechanical stress that could compromise the cylinder.

• Place the cylinder on a stable, level surface using a dedicated stand, clamp, or cradle.
• Ensure the mounting base is clean and free of debris to maintain proper alignment.
• Use non-marring straps or brackets to secure the cylinder without damaging the surface finish.
• Never allow cylinders to stand unsecured or lean against walls.

Industry Standard: Secure all high-pressure cylinders at 2/3 height to prevent toppling.

Connecting the Cylinder

Making leak-tight, secure connections is vital for both safety and sample accuracy.

• Remove protective caps only when ready to connect; keep valve outlets covered otherwise.
• Use appropriate tools (e.g., torque wrench) to tighten fittings—never hand-tighten high-pressure connections.
• Apply thread sealant only if specified; many stainless steel systems use metal-to-metal gaskets.
• Double-check orientation and alignment before tightening to avoid cross-threading.

Warning: Forged steel components are not forgiving—improper installation can lead to sudden failure.

Safety Checks

After connection, perform immediate safety verification to detect leaks or instability.

• Apply a non-corrosive soap solution to all joints, valves, and connections.
• Observe for bubble formation, which indicates a leak—tighten or replace components as needed.
• Check cylinder stability and ensure it remains upright and firmly secured.
• Conduct a low-pressure test before full pressurization to verify system integrity.

Pro Tip: Use electronic leak detectors for toxic or odorless gases like hydrogen or methane.

Maintenance and Repair

Regular maintenance ensures long-term reliability, regulatory compliance, and operational safety.

Routine Inspection

Perform visual and functional inspections before each use and as part of scheduled maintenance.

• Look for dents, cracks, corrosion, or paint degradation that may indicate structural compromise.
• Examine valves, gauges, and safety devices for wear, leakage, or malfunction.
• Check for signs of overheating, such as discoloration or warping.
• Maintain a logbook to track inspection dates, findings, and corrective actions.

Compliance Reminder: Many jurisdictions require formal inspection records for high-pressure vessels.

Cleaning Procedures

Keep cylinders clean to prevent contamination and corrosion.

• Wipe external surfaces with mild detergent and water after each use.
• Avoid abrasive cleaners, steel wool, or chlorinated solvents that can damage the passive oxide layer.
• For internal cleaning, only trained personnel should perform purging, flushing, or passivation using approved methods.
• Ensure complete drying before storage to prevent moisture buildup and internal rust.

Critical Note: Never mix cleaning agents or use solvents incompatible with stainless steel.

Pressure Testing

Hydrostatic or pneumatic pressure testing is required periodically to validate structural integrity.

• Follow manufacturer-recommended intervals (typically every 3–5 years).
• Testing should be performed by certified technicians using calibrated equipment.
• The cylinder is pressurized to 1.5 times its working pressure and held for a specified duration.
• Any permanent expansion, leakage, or deformation results in rejection.

Legal Requirement: Recertification is mandatory in most countries for continued use.

Storage Recommendations

Proper storage preserves cylinder condition and ensures readiness for future use.

• Store in a cool, dry, well-ventilated area away from direct sunlight and heat sources.
• Keep cylinders upright and secured to prevent falls.
• Always replace protective valve caps when not in use.
• Segregate empty and full cylinders; label clearly to avoid confusion.
• Avoid contact with corrosive chemicals, saltwater, or acidic fumes.

Longevity Tip: Store in a controlled environment to extend service life beyond 15+ years.

Expert Recommendation: To maximize safety and performance, always pair high-pressure sample cylinders with compatible regulators, filters, and check valves. Invest in training for operators on proper handling, emergency response, and leak management. When in doubt, consult the manufacturer’s technical data sheet (TDS) or seek certification from a qualified pressure vessel inspector.

Additional Considerations

• Traceability: Each cylinder should have a unique serial number and permanent marking for full lifecycle tracking.
• Customization: Options include special port configurations, integrated gauges, and color-coding for identification.
• Environmental Resistance: 316L offers superior performance in coastal or de-icing salt environments.
• Regulatory Recertification: Mandatory hydrostatic retesting ensures ongoing compliance and safety.
• Supplier Qualification: Choose manufacturers with ISO 9001 certification and documented quality control processes.

Quality and Safety Considerations of Stainless Steel Forged High Pressure Sample Cylinders

Stainless steel forged high-pressure sample cylinders are essential components in industries requiring safe, reliable, and contamination-free storage of pressurized samples—including oil and gas, chemical processing, pharmaceuticals, and environmental testing. Their performance hinges on material integrity, manufacturing precision, and proper handling. This guide outlines the critical quality and safety factors to consider when selecting, using, and maintaining these vital pressure vessels.

Safety Warning: High-pressure cylinders can pose serious risks—including explosion, projectile hazards, and toxic release—if improperly manufactured, handled, or maintained. Always adhere to manufacturer guidelines, regulatory standards (such as ASME, DOT, and ISO), and industry best practices to ensure personnel and operational safety.

Key Quality and Safety Factors

• Material Quality:

  The foundation of a reliable high-pressure cylinder lies in the quality of stainless steel used. Premium-grade stainless steel—typically 316 or 304—offers exceptional corrosion resistance, high tensile strength, and excellent thermal stability. These properties are critical when storing reactive, corrosive, or high-purity samples.

  Inferior materials may corrode, deform, or leach contaminants into the sample, compromising both data integrity and safety. Unlike carbon steel, stainless steel resists rust, minimizing the risk of internal pitting, valve clogging, or structural weakening over time. Always verify material certifications (e.g., mill test reports) to ensure compliance with ASTM or equivalent standards.

• Forging Process:

  The forging method significantly enhances the mechanical properties of the cylinder. Forging involves shaping heated metal under high pressure, which aligns the grain structure and eliminates internal voids or porosity common in cast or welded alternatives.

  Forged cylinders exhibit superior strength-to-weight ratios, improved fatigue resistance, and enhanced durability under cyclic pressure loads. This makes them less prone to cracking, leakage, or catastrophic failure—even under extreme operating conditions. Compared to non-forged (e.g., seamless drawn or welded) cylinders, forged units offer greater reliability for long-term or critical applications.

• Pressure Ratings and Compliance:

  Stainless steel forged high-pressure sample cylinders are typically rated between 3,000 and 6,000 psi (207–414 bar), with some specialized models exceeding these limits. These ratings are determined through rigorous hydrostatic and burst testing to ensure safety margins (usually 3:1 or 4:1 burst-to-working pressure ratio).

  Using a cylinder beyond its rated pressure—or in environments with extreme temperatures—can lead to deformation, leaks, or rupture. Always match the cylinder’s pressure and temperature ratings to your operational requirements. Look for clear labeling of working pressure, test pressure, expiration date, and compliance marks (e.g., ASME UG-125, DOT-SP, PED).

• Regular Inspections and Maintenance:

  Proactive inspection is vital to detect early signs of wear or damage. Conduct visual and non-destructive examinations (NDE) at regular intervals—typically annually or per regulatory schedule—to identify:

  • External corrosion, pitting, or discoloration
  • Cuts, dents, scratches, or gouges in the cylinder wall
  • Cracks near welds, neck threads, or base
  • Valve damage or leakage

  Damaged cylinders should be immediately removed from service and sent for requalification or retirement. Hydrostatic retesting is often required every 3–5 years, depending on jurisdiction and usage.

• Proper Handling and Storage:

  Safe handling practices are crucial due to the stored energy in pressurized cylinders. Never drop, roll, or drag cylinders, as impact can compromise structural integrity or damage valves—potentially leading to uncontrolled release.

  Always use protective valve caps when transporting or storing to shield the outlet from impact. Secure cylinders in upright positions using chains or stands to prevent tipping. Avoid exposure to extreme heat, direct sunlight, or incompatible chemicals. When in use, ensure proper ventilation and follow lockout/tagout procedures during maintenance.

Expert Tip: Implement a cylinder tracking system that logs inspection dates, test results, pressure cycles, and maintenance history. This not only ensures regulatory compliance but also helps predict service life and prevent unexpected failures.

Additional Safety Recommendations

• Train all personnel in high-pressure equipment safety and emergency response procedures.
• Use only compatible regulators, fittings, and tubing designed for high-pressure stainless steel systems.
• Depressurize cylinders before inspection, maintenance, or transport.
• Label cylinders clearly with contents, pressure, date, and hazard warnings.
• Dispose of or requalify expired or damaged cylinders through certified facilities.

Stainless steel forged high-pressure sample cylinders are engineered for safety and reliability, but their performance depends on informed selection, diligent maintenance, and strict adherence to safety protocols. By prioritizing material quality, manufacturing standards, and proper handling, organizations can ensure the integrity of their samples and the safety of their personnel.

Frequently Asked Questions About Stainless Steel High-Pressure Sample Cylinders

Stainless steel forged high-pressure sample cylinders are the preferred choice in scientific and industrial environments due to their exceptional durability, corrosion resistance, and ability to maintain structural integrity under extreme conditions. These qualities are critical when preserving the purity and stability of sensitive samples used in research, chemical analysis, and material testing.

• Durability: Stainless steel withstands high mechanical stress, making it ideal for repeated pressurization cycles without deformation.
• Corrosion Resistance: Unlike carbon steel or aluminum, stainless steel resists oxidation and chemical degradation, even when exposed to aggressive solvents or humid environments.
• Thermal Stability: These cylinders retain strength across a wide temperature range, ensuring reliable performance in cryogenic or heated applications.
• Non-Reactivity: The inert nature of stainless steel prevents unwanted chemical interactions with stored samples, preserving sample integrity.

These combined properties make stainless steel forged cylinders the gold standard for laboratories, pharmaceutical development, petrochemical industries, and environmental testing facilities where sample contamination or equipment failure is not an option.

The forging process is a critical factor in enhancing the mechanical strength and reliability of high-pressure sample cylinders. Unlike cast or machined components, forged stainless steel undergoes controlled plastic deformation under extreme heat and pressure, which fundamentally improves its internal structure.

• Grain Flow Optimization: Forging aligns the metal’s grain structure along the shape of the cylinder, creating a continuous, unbroken grain path that enhances toughness and fatigue resistance.
• Elimination of Defects: The compressive forces involved in forging close internal voids, porosity, and micro-cracks commonly found in cast metals, resulting in a denser, more uniform material.
• Increased Tensile Strength: Forged components typically exhibit 20–30% higher tensile and impact strength compared to their non-forged counterparts.
• Improved Safety: The enhanced structural integrity reduces the risk of sudden failure under pressure, making forged cylinders safer for handling volatile or high-energy samples.

Because of these advantages, forged cylinders are trusted in mission-critical applications where failure could lead to data loss, equipment damage, or safety hazards.

Safety is paramount when working with high-pressure equipment. To minimize risks and ensure long-term reliability, follow these essential safety practices:

• Compliance with Standards: Use only cylinders manufactured and tested according to international safety standards such as ASME, ISO 7866, or PED (Pressure Equipment Directive).
• Regular Inspections: Conduct visual and non-destructive testing (NDT) inspections at scheduled intervals to detect cracks, corrosion, or deformation.
• Pressure Rating Adherence: Never exceed the cylinder’s maximum allowable working pressure (MAWP). Always match the cylinder rating to the application’s operating conditions.
• Contamination Control: Prevent foreign materials, oils, or incompatible chemicals from entering the cylinder, as they may cause reactions or pressure build-up.
• Proper Disposal: Retire and safely decommission cylinders that show signs of damage, wear, or have exceeded their service life. Do not attempt to repair or reuse compromised units.

Implementing these protocols significantly reduces the risk of accidents and ensures safe, efficient operation in laboratory and industrial settings.

Proper maintenance is key to maximizing the service life and performance of high-pressure sample cylinders. Implementing a routine care plan helps prevent premature degradation and ensures consistent reliability:

• Post-Use Cleaning: After each use, clean the exterior with a mild detergent and dry thoroughly to remove residues that could lead to corrosion.
• Regular Inspections: Check for surface cracks, pitting, dents, or thread damage before and after use. Early detection allows for timely intervention.
• Pressure Testing: Perform hydrostatic or pneumatic requalification tests at manufacturer-recommended intervals (typically every 3–5 years).
• Proper Storage: Store cylinders in a cool, dry, well-ventilated area away from direct sunlight, moisture, and corrosive chemicals. UV exposure and humidity can accelerate material fatigue.
• Protective Caps: Always keep valve protection caps securely in place when not in use to prevent damage to valve stems and ports.

By following these maintenance best practices, users can extend cylinder lifespan, maintain certification compliance, and ensure operational safety.

Yes, stainless steel forged high-pressure sample cylinders are engineered to perform reliably across a broad temperature spectrum—typically ranging from **–196°C (cryogenic liquid nitrogen temperatures) to +200°C**. This thermal resilience makes them suitable for a wide array of demanding applications.

• Cryogenic Use: At extremely low temperatures, stainless steel retains ductility and does not become brittle, unlike many other metals.
• High-Temperature Stability: Even at elevated temperatures, the alloy maintains strength and resists oxidation, preventing structural weakening.
• Thermal Cycling Resistance: The forged structure handles repeated expansion and contraction without cracking or fatigue.
• Material Certification: For extreme environments, ensure the cylinder is made from appropriate grades (e.g., 316L stainless steel) and certified for the intended temperature range.

To ensure safety and longevity, always operate within the specified temperature limits and conduct additional inspections if the cylinder is frequently exposed to thermal extremes.