thermal acoustic insulationZMT insulation from Elasto Proxy is a thermal acoustic composite that also resists fire and chemicals. Applications include firewalls and engine bays.

Elasto Proxy custom-fabricates silicone composites that combine thermal and acoustical insulation with resistance to flame and fire, chemicals and oil, and electrostatic energy. These multi-layer materials consist of a silicone foam, neoprene skin, aluminum facing, and pressure-sensitive adhesive (PSA). Applications for Elasto Proxy’s ZMT insulation include the firewalls and engine bays in mobile equipment and military vehicles. ZMT also meets flame-resistance requirements for the mass transit and aviation industries.

Application Requirements

As we learned in Part 1 and Part 2 of our recent series about thermal acoustic insulation, excessive heat and sound can endanger personnel and damage equipment. Yet some applications also require resistance to other hazards, including some that may seem routine. For example, engine bay insulation in military vehicles may need to withstand frequent washdowns with water and detergents. Thermal acoustic insulation for ground-based equipment must withstand engine oil and automotive chemicals. Unless the right type of thermal acoustic materials are used, a multi-layer composite can delaminate or deteriorate.

The aviation and mass transit industries also need thermal-acoustic insulation that does more than resist heat and sound. On the ground or in the air, spills from damaged fuel tanks can cause fires that penetrate the cabin. Fireproof insulation in an airplane’s floor and sidewalls is critical, but manufacturers also need fire resistant materials for interior components. Trains and buses face the risk of fire, too, both from outside and inside the cabin. By using thermal acoustic insulation that can delay the spread of flames and avoid the release of toxic gases, the mass transit industry can keep passengers safe and comfortable.

Material Properties

The silicone foam in ZMT insulation combines excellent high-temperature resistance with a compression set that’s comparable to natural rubber even at elevated temperatures. Silicone also repels water, resists weathering, won’t dry out, and is difficult to ignite. When silicone does burn, this synthetic rubber turns to a grayish ash and won’t emit toxic chemicals. The neoprene facing that’s used with ZMT insulation also has a relatively high burn point. Neoprene provides resistance to water, chemicals, oils, and cleaning agents, too. The aluminum foil reflects radiated heat and provides resistance to fluids and tearing.

The PSA that’s used with ZMT insulation resists heat, humidity, mild plasticizers, some solvents, and UV light. Importantly, this double-sided PSA tape supports attachment without the use of a flammable primer. The minimum application temperature is 50° F, and the PSA resists -35° to 250° continuous-use temperatures.  As a “best of both worlds” solution, this PSA features a silicone adhesive on the foam bonding side and an acrylic adhesive on the end-use side. Silicone adhesives resist higher temperatures. Acrylic PSAs provide reliable adhesion to metal surfaces such as aluminum and stainless steel.

ZMT has a temperature range of -60° F to +400° F and a noise reduction coefficient (NRC) of 0.3. Elasto Proxy’s Z3T thermal acoustic insulation has greater sound absorbing properties, but ZMT is recommended for many applications because of its unique balance of properties. In addition to standard thermal acoustic materials such as ZM, Z3T, and ZTBRA, Elasto Proxy can also create custom insulation sandwiches

Performance Testing

ZMT thermal acoustic insulation has been tested according to various ASTM methods for smoke density, flame spread index, limiting oxygen index, dielectric constant, arc resistance, and electrical insulation resistance. In thicknesses of 1/8” or greater, this silicone composite passes the UL 94 vertical burn test. ZMT insulation also complies with the Boston Fire Department Chair Test and passes the Bombardier SMP 800-C test for fire, smoke, and toxicity (FST).

ZMT insulation meets Federal Aviation Regulations (FAR) from the Federal Aviation Administration (FAA), part of the U.S. Department of Transportation. Specifically, ZMT passes ZAR 25.853 (A-1 and B) and FAR 25.856 (A-1). The first standard, ZAR 25.853, is an FAA Advisory Circular (AC) about flammability requirements for aircraft seat cushions. FAR 25.856 is an FAA AC about thermal acoustic insulation for burnthrough protection, materials that are installed in the aircraft’s sides or underneath the flooring.

How Can We Help You?

Many thermal and acoustical materials are available, so it’s important to pick a partner who can help you with insulation selection. It’s also critical to choose a custom-fabricator who understands how to arrange each material into a sandwich-like structure that meets all of your requirements. Application knowledge and technical expertise are essential, too. Plus, you need a partner who uses the most cost-effective fabrication techniques. That’s why after lamination, Elasto Proxy uses water jet cutting to make fine, fast cuts with no tooling charges.

From prototyping to low-to-medium volume production, Elasto Proxy is the right choice for thermal acoustic insulation. How can we help you? To get started, contact us.

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