Boiler and engine rooms are usually thought of as hot, uncomfortable places to work. Add the space constraints of marine installations and conditions can range from inhospitable to downright dangerous, as piping systems can exceed temperatures of 1,000 ºF (537 ºC). So when a fleet of drilling ships reported that their exhaust insulation had come apart and needed to be replaced, it was all hands on deck for Firwin Corporation, a manufacturer of insulation solutions.

The customer initially requested construction of removable insulation blankets of a specific size and thickness to cover the exhaust flexes and the upper and lower flanges for six generator sets. However, Firwin noted that without knowledge of the parts being insulated, they could not guarantee that the customer’s requested sizes for these blankets would fit properly.

Because the insulation blanket’s thickness increases the effective outside diameter of the pipe, Firwin’s engineers would essentially need to increase the pipe diameter by the blanket's thickness at each end of the pipe to arrive at the appropriate insulating diameter. It’s one of the “tricks of the trade” that experts know and can use to assist end users.

“If a customer lets us know what they want to cover, we can recommend something more appropriate, as the blanket size they specify might not be the most optimal,” said Sid Tannenbaum, marketing manager with Firwin. “This customer agreed to let us see what they wanted to do, and we designed something totally different that was much more efficient.”

Firwin offered designs of a single blanket, similar to the customer’s existing solution, as well as a three-blanket solution for the flex and flanges. The customer chose the three-blanket solution for its greater flexibility and easier installation and removal.

Varieties of Insulation Blankets for Marine Vessel Applications

Many engineers looking for insulation solutions don’t stop to consider the variety of options that exist to meet the list of safety needs in marine and other applications. Insulation blankets are offered in many different materials and forms to meet each individual application.

Insulation blankets are essential for effective performance and safety for piping, exhaust systems and personnel due to the limited space afforded in engine rooms, galleys and gangways. Insulation blankets reduce ambient heat load, protect heat sensitive sensors and equipment, assist in fire prevention, maximize effectiveness of exhaust catalytic purifiers and filters and reduce risk of injury due to contact with heated surfaces.

Some insulation materials used for heat insulation are also effective sound absorbers, with a noise reduction coefficient rating of 0.75 for one inch of thickness. This can be improved further by using dense membranes in composite layers.

The qualities and dimensions of an insulation blanket may also vary between permanent and removable designs.

Removable insulation blankets are designed in conveniently sized panels or sections that can be easily installed or removed by shore technicians or the ship’s crew if necessary. When maintenance or inspections are required, the crew need only remove the necessary blankets.

“You won’t want to permanently encapsulate maintenance-sensitive parts in insulation because if you need to get to it you’ll have to break off your insulation and then get it replaced,” said Tannenbaum. “In this case you can get a custom removable cover, which is usually laced up around the part until you need to access it. When you need access to the part, you can easily unlace it to take off the blanket.”

Permanent insulation is best for long pipe runs that don’t require maintenance.  Whether cut and fitted on site or at the insulation manufacturer’s facility, permanent insulation is tricky to remove and difficult to replace, but has unique advantages.

Hard Coat Composite is a type of permanent insulation used in marine applications in cases where longevity is paramount over removability, Tannenbaum explained.

“Permanent insulation solutions, like our Hard Coat product, can help in cases with space constraints and can be thinner than a normal blanket. For this type of insulation, the customer would need to dismantle the engine parts they want insulated and ship the parts to us. We apply the insulation here in our factory and we ship it back with the insulation coated on and ready to go for them to reassemble.”

Safety and Material Selection for Marine Insulation Blankets

Both replaceable and permanent insulation solutions need to meet coast guard, UL, Lloyds and DNV requirements to effectively address concerns such as flammability for marine applications.

“Our blankets are fire retardant, so they don’t catch fire,” Tannenbaum said. “The only danger of having a blanket on a hot part is if there is an engine oil leak that spills on the underside of the blanket. Customers can use a permanent hard coat to avoid this or we can provide an impermeable, liquid-proof inner liner that doesn’t allow any oil to seep into the insulation material itself.”

Blankets are typically constructed with mesh fiber glass and silicon, but the particulars of the design can change for the application.

Firwin offers a range of materials, including silicone impregnated fiberglass, aluminized fiberglass, fiberglass, CMS wool and stainless-steel mesh, each for different applications.

“We have an insulation solution with a stainless-steel mesh on the side resting on the hot component, with silicon impregnated fiberglass material on the cold side or where the person would touch,” Tannenbaum added. “We have other materials to use for under and top sides as well. Sometimes an application might need a liquid barrier so that fiberglass doesn’t get exposed to any liquid. In this case, we recommend a different inner liner that’s not a mesh that covers the insulation completely and can be oil or water proofed.”

The outer layer of a blanket can also be designed to withstand temperatures of other heated parts in its proximity in tight areas.

Installation and Advice from Firwin Corporation

Removable insulation blankets can usually be installed quite easily by the customer, but for applications requiring particularly thick and heavy blankets, installation can become tricky. Customers must include spatial allowances in a design consultation.

“Even though you might need a thick blanket to get the heat reduction you want, you might not have enough space between the part you want to cover and the part next to it,” Tannenbaum said. “The blanket typically needs a bit of airspace to let the heat escape. In that case customers can go with a thinner, higher temperature insulation, where a quarter inch thickness can give just as much insulation as a full inch, but there’s a price premium there and so you have to use that sparingly.”

Firwin offers installation drawings as well as videos and pamphlets on their to guide customers when installing.

The best advice that Tannenbaum can offer for anyone interested in insulation blankets for marine applications or otherwise, is to avoid skimping on the details and work with insulation providers as closely as possible for the best results.

“Allow the insulation company to specify the right material with the right design and blanket makeup for your application. Provide pictures, drawings, dimensions and goals to help ensure you get the best insulation product you can. It’s also good to educate yourself beforehand on what to look for in a supplier and to know what questions they should be asking you.”

For more information, visit the Firwin Corporation website to access their collection of e-books, whitepapers and videos.

Firwin Corporation has sponsored this post.  All opinions are mine.  --Kagan Pittman