What Are Sealing Strips And Why Do They Matter?

Sealing strips are flexible profiles made from rubber or elastomer materials. Their main job is simple but critical: stop water, air, dust, vibration, and noise from entering or escaping an area.

You will find sealing strips everywhere — hatch covers on ships, engine room access doors, tugboat wheelhouse windows, container doors, port equipment cabinets, industrial enclosures, even loading ramps. A well-designed seal protects assets, extends service life, and reduces maintenance downtime.

In marine and heavy industrial environments, sealing performance is not just about comfort. It's about corrosion control, safety, and compliance. If saltwater enters an electrical box, or if rainwater seeps into a control cabinet on the jetty,  you don't just get rust — you get failures. Because working conditions vary (UV, salt spray, oil, temperature, compression load, etc.), not all sealing strips are the same. Different rubber compounds exist for different problems. Below are the most commonly used sealing materials.

Common Rubber Materials Used in Sealing Strips

1. EPDM Rubber (Ethylene Propylene Diene Monomer)

Why it's popular
EPDM is one of the most widely used materials for weather seals.

Key properties

· Excellent resistance to sunlight (UV), ozone, rain, and general weathering

· Good flexibility in both low and moderate temperatures

· Electrically non-conductive

· Weak against oils, fuels, and many hydrocarbons

Typical temperature range
Approx. −40°C to +120°C (and in short periods even higher depending on grade)

Where EPDM is used

· Door and window sealing on vessels and port equipment cabins

· Hatch covers and access panels exposed to rain and splash

· HVAC enclosures and ventilation frames

· Truck and container doors

When to choose EPDM
Use EPDM when the main enemy is weather, not oil. It’s ideal for outdoor sealing exposed to sunlight and seawater spray but not in direct contact with diesel or hydraulic oil.

2. Neoprene / CR Rubber (Chloroprene Rubber)

Why it's considered “balanced”
Neoprene offers a good compromise between weather resistance and oil resistance.

Key properties

· Good resistance to aging, ozone, and moderate UV

· Moderate resistance to oils and greases

· Good mechanical strength and abrasion resistance

· Self-extinguishing behavior in some grades (useful for safety)

Typical temperature range
Approx. −30°C to +100°C

Where Neoprene is used

· Marine door and window seals on workboats and tugboats

· Edge protection strips around sharp steel sections

· Vibration isolation pads between metal contact surfaces

· Seals for electrical cabinets where there is occasional oil mist

When to choose Neoprene
Choose Neoprene when you need one material that “does everything fairly well”: outdoor weather + splash of oil + mechanical contact. It’s common in marine hardware and port cranes.

3. NBR / Nitrile Rubber (Acrylonitrile Butadiene Rubber)

Why oil resistance matters
NBR is the go-to material when contact with oil, fuel, or lubricants is unavoidable.

Key properties

· Excellent resistance to petroleum-based oils and fuels

· Strong resistance to hydraulic fluid, diesel, lubricants

· Good mechanical strength

· Weaker UV and ozone resistance than EPDM unless specially protected

Typical temperature range
Approx. −20°C to +100°C (higher for special grades)

Where NBR is used

· Engine room doors and service hatches

· Seals around hydraulic power units, pumps, and valve manifolds

· Fuel system access panels and tank covers

· Industrial equipment bases where oil leakage is expected

When to choose NBR
Use NBR if oil exposure is the main risk. This is common near winches, power packs for quick release hooks, hydraulic actuation panels, and mooring load monitoring systems.

4. Silicone Rubber

Why high temperature is important
Silicone is chosen for temperature stability and cleanliness.

Key properties

· Very wide temperature tolerance

· Excellent flexibility and compression set recovery even after long service

· Inherently inert and low-toxicity (often used in food and medical environments)

· Weaker tear/abrasion resistance compared to industrial rubbers like NBR or Neoprene

· More expensive than standard elastomers

Typical temperature range
Approx. −50°C to +200°C (depending on grade)

Where Silicone is used

· High-temperature enclosures, lighting housings, engine exhaust covers

· Control cabinets and electronics that cannot tolerate moisture ingress

· Instrument panels and sensor housings for monitoring equipment

When to choose Silicone
Use Silicone when:

· High heat or thermal cycling is expected

· Seal must remain soft and elastic over a long period

· Cleanliness and low off-gassing are required

This is common around sensors, monitoring units, intelligent berthing system enclosures, and electronics in harsh dockside environments.

5. Sponge / Foam Rubber (EPDM Foam, Neoprene Foam, etc.)

Besides solid rubber profiles, many sealing strips are made from closed-cell sponge rubber.

What “closed-cell” means
The internal structure is full of tiny sealed bubbles. When compressed, it deforms and fills gaps. When pressure is released, it recovers. Because the cells are closed, water does not easily pass through.

Key advantages

· Compresses easily to fill irregular gaps

· Good for doors, hatches, inspection covers with uneven surfaces

· Lower closing force needed (the door/cover doesn't need huge torque to seal)

· Good acoustic and vibration damping

Typical uses

· Electrical cabinets on jetties and quay walls

· Instrument boxes for mooring load cells, DGPS receivers, laser sensors, etc.

· Removable panels that require frequent access for inspection and maintenance

Foam seals are often supplied with self-adhesive backing: peel, stick, compress, done.

How to Choose the Right Sealing Material

When selecting a sealing strip, consider these factors:

1. Environment

o UV / sunlight exposure?

o Saltwater spray or immersion?

o Ozone / outdoor weathering?
→ EPDM and Neoprene perform well outdoors; Silicone for extreme temp.

2. Contact with oil or fuel

o Hydraulic oil leakage nearby?

o Diesel vapors present?
→ NBR (Nitrile) is usually the safest choice.

3. Temperature

o Normal ambient, or close to engines / hot pipes / control cabinets with high heat?
→ Silicone is preferred for high temperature zones.

4. Compression and movement

o Is the seal static (just sits there)?

o Or is it repeatedly opened/closed (e.g. hatch door)?

o Does it need to absorb vibration between steel structures?
→ Sponge/foam profiles reduce vibration and require less closing force.

5. Mechanical wear

o Will forklifts, chains, tools, or mooring lines rub this surface?
→ Neoprene and NBR have better abrasion resistance than silicone.

6. Standards / Compliance

o Some sites (especially oil & gas terminals and LNG berths) require specific fire performance, anti-spark behavior, or certain flame retardant properties.

o Neoprene is often chosen in these environments because of its fire behavior and general resistance profile.

Typical Applications in Marine and Port Environments

· Hatch cover seals / watertight doors
EPDM or Neoprene strips are installed around cargo hold covers, access hatches, and bow doors to keep seawater out.

· Wheelhouse / bridge windows on tugs and workboats
Custom-molded sealing profiles reduce vibration, block rainwater at high spray angles, and cut wind noise.

· Quayside electrical cabinets and monitoring boxes
Closed-cell sponge strips prevent moisture, salt fog, and dust from entering PLC panels, load monitoring systems, or intelligent berthing control units.

· Mooring and fender monitoring systems
Sealing strips are used around sensor housings (load cells, displacement sensors, laser distance sensors) to protect electronics from splash and impact.

· Industrial machinery and hydraulic systems
NBR-based seals are mounted around pump covers, oil tanks, and hydraulic manifolds to stop oil leakage and protect workers from slipping hazards.

Installation Notes

A sealing strip only works if it is installed correctly. Key points:

· Surface preparation
The contact surface should be clean, dry, and free of rust flakes, peeling paint, or oil films. Contamination prevents proper compression and sealing.

· Compression design
Most sealing strips are designed to work under a specific compression rate (for example, 25–40% squeeze for a foam profile). Too little compression = leaks. Too much = permanent deformation and early failure.

· Fastening method

o Push-in channel / mechanical clamping

o Adhesive backing (PSA tape)

o Bolted retainer strips
The correct method depends on vibration level and how often the panel will be opened.

· Inspection / replacement
Seals are consumables. In marine duty, UV + salt + mechanical wear will age any elastomer. Regular visual inspection for cracks, hardening, flattening, or tearing helps avoid more serious damage later (flooded cabinet, corroded terminal, etc.).

Why High-Quality Sealing Matters for Ports and Vessels

Even a small gap can allow saltwater intrusion. Saltwater + electricity = corrosion, short circuit, unplanned shutdown.
In modern ports, a lot of value is concentrated in smart systems: mooring load measurement, remote release hooks, berthing assistance displays, DGPS receivers, berth occupancy sensors. All of these rely on electronics mounted extremely close to the water.

JIER Marine Sealing Capability

JIER Marine supplies marine-grade sealing strips in EPDM, Neoprene (CR), NBR, Silicone, and closed-cell sponge profiles. Products are available in custom cross-sections, hardness (Shore A), and lengths, and can be supplied pre-cut for hatches, cabinet doors, sensor housings, and port equipment.

We support:

· Weather-resistant EPDM strips for hatch covers and deck doors

· Oil-resistant NBR seals for hydraulic power units and mooring systems

· Neoprene and sponge profiles for vibration isolation and panel sealing

· Custom shapes for intelligent berthing / monitoring terminals

Our goal is simple: keep water, dust, and oil out — and keep your equipment working longer with less maintenance.