Guidelines for the Storage of Rubber Products

Rubber products play an important role across every industry. From seals and O-rings to hoses, gaskets and vibration mounts, these materials are relied upon for their flexibility, resilience and sealing properties. Yet, one of the most common causes of rubber failure isn’t poor design or manufacturing defects – it is prolonged improper storage. Rubber naturally degrades over time and that process can dramatically accelerate when exposed to the wrong environmental conditions.

To help prevent this, the International Organization for Standardization (ISO) created ISO 2230:2002, titled “Rubber Products – Guidelines for Storage”. This standard outlines how rubber materials should be stored, inspected and maintained to minimise aging and preserve performance. It applies to both natural and synthetic rubbers, as well as vulcanised and thermoplastic materials. This provides a universal reference for anyone handling or storing rubber components.

The core purpose of ISO 2230:2002 is to slow down the natural deterioration that rubber undergoes when it is exposed to certain environmental factors. Over time, heat, light, oxygen, ozone and humidity can all contribute to changes in the material's physical structure. These changes often manifest as hardening, cracking or loss of elasticity. Once a rubber part begins to degrade, it can no longer perform its sealing function effectively. By following the recommendations in ISO 2230:2002, storage conditions can be controlled so that rubber products maintain their original properties for as long as possible.

According to ISO 2230, several environmental elements can accelerate the degradation of rubber materials. The standard provides guidance on how to control each one:

Temperature is one of the most influential factors in rubber storage. ISO 2230 recommends that rubber components be kept at a temperature between +5°C and +25°C (41°F to 77°F). Within this range, the chemical reactions that cause aging occur much more slowly. High temperatures, even for short periods, can significantly accelerate oxidation and cause the material to become hard or brittle. On the other hand, storing rubber in freezing conditions can make it stiff and more prone to cracking when flexed. Ideally, storage areas should maintain a stable, moderate temperature throughout the year, away from heat sources like radiators, steam pipes or direct sunlight.

Humidity is another key consideration. Excess moisture can lead to surface blooming or even microbial growth, which can affect the appearance and mechanical performance of rubber. ISO 2230 advises maintaining a relative humidity below 65 percent. In humid climates, dehumidifiers, air conditioning systems, or the use of desiccants in packaging may be necessary to control moisture levels. The aim is to keep the environment dry enough to prevent degradation while avoiding overly dry air as this can also cause some rubber types to lose flexibility.

Light, particularly ultraviolet (UV) light, has a destructive effect on many rubber compounds. Continuous exposure to sunlight or fluorescent lighting can cause oxidation and cracking on exposed surfaces. To prevent this, rubber products should always be stored in opaque or UV-resistant containers or in areas where light exposure is minimal. A dark storeroom or a closed cabinet is ideal. Even artificial lighting can have harmful effects if the bulbs emit UV radiation, so covering light fixtures or using filtered lights is a good preventive measure.

Ozone is one of rubbers most damaging enemies. It causes a specific type of cracking—often called ozone cracking—that appears on stretched or tensioned surfaces. Airtight packaging, such as sealed polyethylene bags, can help protect against both ozone and oxygen exposure. Reducing the amount of circulating air around stored items further minimizes oxidation, extending the life of the rubber.

Rubber components can deform if stored improperly, especially if they are left under tension or pressure for long periods. For example, if a rubber seal is hung on a hook or wrapped tightly in cling film, it may take on a permanent set or flatten out. ISO 2230 recommends that rubber be stored in a relaxed and unstressed condition. Larger components should be supported on flat surfaces and smaller items should be loosely stored to maintain their shape. Avoid stacking heavy parts on top of one another, as the pressure can also cause distortion.

Another guideline in ISO 2230 is the need to keep rubber free from chemical contamination. Rubber should not be stored near solvents, oils, fuels, cleaning agents or acids, as vapors from these substances can cause swelling or softening. Even simple household cleaners or industrial lubricants can degrade rubber surfaces over time. Storage areas should be clean, dust-free and well-ventilated, with no direct contact between rubber and metal surfaces that might corrode or transfer contaminants.

Although ISO 2230:2002 does not specify exact shelf lives for rubber materials, it emphasises that all rubber products have a finite storage life due to natural aging processes. The expected lifespan varies considerably depending on the rubber type and compound formulation—materials such as silicone or fluorocarbon rubber can remain stable for well over a decade under proper conditions, while natural rubber and nitrile compounds may begin to degrade sooner. Factors like curing agents, fillers and plasticisers also influence longevity, meaning even two rubbers that appear similar may age at different rates. When stored correctly according to ISO 2230 guidelines, most general-purpose rubbers can be expected to maintain their physical properties for at least five to ten years. However, this figure should always be confirmed with the manufacturers data, as some products are specifically formulated for long-term resilience while others are designed for short-term flexibility.

Because degradation often begins internally and may not be visible at first, routine inspection is essential to ensure that stored rubber components remain safe and effective. A good inspection process involves both visual and tactile checks—looking for changes in colour, cracking, surface stickiness or hardness. Any sign of surface dullness, blooming or tackiness may indicate chemical change or the migration of additives, both of which can affect performance. Rubber that feels stiff, brittle or oily to the touch should be replaced immediately rather than reused. Establishing a regular inspection schedule—typically every six to twelve months for stock—helps identify problems early and prevents failures during installation. Many organisations also use traceability systems, such as storage codes or shelf-life classifications based on ISO 2230, to track the condition of inventory and ensure products are used within their recommended service window. By combining careful monitoring with proper documentation, companies can maintain confidence in the reliability and safety of every stored rubber component.

Good storage management goes far beyond simply keeping rubber in a cool dry place. One of the most effective strategies for preserving the quality of rubber components is to store them in their original packaging for as long as possible. The packaging supplied by manufacturers is often designed to act as a protective barrier against air, ozone, and light exposure. By keeping rubber seals and gaskets sealed inside their original containers, you minimise the risk of contamination and environmental degradation. It’s also important to ensure that the packaging itself remains intact and dry—if a box or bag becomes damaged, it should be replaced to maintain protection. However, sometimes additional packaging materials, such as cling film, are used to protect the rubber item from damage during transit. These should be removed so that the rubber is not held tightly for a prolonged period of time.

Another crucial aspect of good storage practice is inventory management and identification. All stored rubber items should be clearly labelled with batch numbers, manufacturing dates (if applicable) and delivery information. This traceability ensures that users can easily identify the age of each component and confirm its suitability for use. Applying a “first-in, first-out” (FIFO) rotation system is recommended to prevent older stock from remaining on the shelf for extended periods. Over time, even well-preserved rubber will eventually reach the end of its recommended storage life, so rotating inventory helps minimize waste and ensures that the oldest stock is used first. Maintaining an organized storage area—preferably with dedicated shelving and clearly defined zones for different product types—can greatly reduce handling errors and confusion.

Careful handling and environmental awareness are also key to maintaining the integrity of stored rubber components. Rubber should not be unnecessarily unwrapped or bent, as repeated movement can accelerate aging and cause surface stress. Large items should be supported to prevent deformation, while smaller items should be stored flat or in a relaxed position to maintain their natural shape. It is also beneficial to inspect the storage environment periodically, checking that temperature, humidity and cleanliness remain within the recommended ranges set out in ISO 2230. Keeping storage rooms free from dust, oils and chemical vapours reduces the likelihood of surface contamination. By combining careful packaging, systematic stock control and consistent environmental monitoring, companies can extend the service life of their rubber components and ensure that each product performs exactly as intended when it is finally put into use.

Following ISO 2230:2002 is a case of product reliability. When rubber materials are stored under controlled conditions, their physical properties remain consistent, which means they perform as expected when installed. Failure to adhere to these guidelines can lead to premature cracking, hardening or deformation. All of which compromise sealing effectiveness and increase the risk of leaks or system failures.

By applying the principles outlined in ISO 2230, companies can extend the usable life of their rubber components, reduce waste and avoid costly downtime or replacements. Whether it’s a warehouse storing industrial seals or a maintenance department holding spare gaskets, proper storage is an investment in reliability and performance.

Seals Direct is a leading manufacturer and supplier of rubber seals, trims and associated products. Our experienced team is able to advise on the best product and material for your application, that takes into account the intended appliaction of your chosen rubber profile. Please give us a call on 01425 617722 or contact us by email at sales@sealsplusdirect.co.uk.