With today’s energy costs, many heat treaters may be considering furnace replacement. A more economical option may be to perform an energy analysis and upgrade the furnace insulation system.

Fig. 1. Optimum insulation systems include ceramic fiber and mineral wool

Operating furnaces today is a costly proposition, especially when energy costs are considered. Furnaces are expensive to buy, and they are also costly to maintain and operate. Many operators choose to upgrade rather than replace older equipment to save on the up-front costs. When older furnaces are upgraded, the energy efficiency is a key consideration. For help in choosing the optimum insulation systems, many companies turn to specialists in this field. GIS, Inc. – with 30 years of experience – is one such company.

Today’s furnace requirements are much more demanding. Furnaces need to be energy efficient, environmentally safe and user-friendly. They also need to protect the operator from hazardous working conditions. Additionally, future maintenance costs and availability of replacement parts are key considerations. Refractory/insulation packages – available for furnace rebuilds – help to achieve all of these requirements (Fig. 1).

Computerized Energy Analysis

One of the advanced benefits available today is the computerized energy analysis. These programs are tailored to the customer’s special needs and can calculate the most economic insulation package based on return on investment (ROI). The analysis includes fuel costs, installation costs, taxes and future maintenance considerations. Many furnace operators include environmental calculations of greenhouse gases – CO2, NOx and carbon equivalent (CE) – as well. An optimized insulation system can result in a significant reduction in fuel consumption.

Composite Insulation Systems

Computer-recommended composite insulation systems optimize performance. An example of this is a hot side of a furnace at 1800°F. Computer calculations recommend that a ceramic blanket or ceramic module be used on the hot side. The computer program indicates that a second layer of insulation – on the cold-face side – can economically provide improved performance.

For other applications, the program will similarly recommend specific, detailed, manufactured products based on the economic, environmental and energy considerations. This up-to-date analysis is currently being used for furnaces, ovens, heat-recovery ducts and industrial piping systems.

Fig. 2. Lab counter-top ovens require specific insulation design

Furnace Size Ranges

Insulated systems – completely designed for large furnaces to lab counter-top mini ovens – require specific design criteria (Fig. 2). Obtaining owner/engineer design requirements helps to identify the multitude of variables that exist. Definitive computer analysis helps management make the correct ROI decisions.

Fig. 3. Environmentally safe, high-temperature cloth insulation

Textile Industrial Cloth

Environmentally safe, high-temperature cloth products are an important ingredient for today’s furnaces, ovens and other high-temperature equipment (Fig. 3). Temperature ranges of 500-3000°F include applications such as expansion joints, gaskets, welding blankets, pipe and hose covering as well as tapes and ropes.

Fig. 4. Removable insulation cover for industrial flange

Insulation products can be manufactured into removable insulation covers to fit industrial fittings, valves and flanges (Fig. 4). Turbine blankets are another end product. Field measurements are a must for exact fit.

Many facilities with high-temperature equipment also have numerous lower-temperature applications that could benefit from in-place covering/insulation. The following is a list of typical applications:
  • Pipe wrap (Fig. 5)
  • Protection of hose lines
  • Exhaust manifold wrap
  • Protection of cable
  • Heat shields

Fig. 5. Pipe wrap insulation

In-place performance means energy savings. As an example, a 6-inch, 150-pound flange operating at 387°F saves $370 per year per flange when insulated. Don’t debate – insulate. IH

For more information: Contact Jack Hartzell at GIS, Inc. Insulation Services, 23 Furnace St., McKees Rocks, PA 15136; tel: 412-771-8860; fax: 412-771-8918; e-mail: jack@gisinsulation.com; web: www.gisinsulation.com

Additional related information may be found by searching for these (and other) key words/terms via BNP Media SEARCH at www.industrialheating.com: energy analysis, insulation, energy efficiency, graded insulation

SIDEBAR: Energy Audit Calculation

The computer results of an uninsulated 10-foot-diameter, 30-foot-high holding tank show a 224,415 BTU/hour savings by using 2-inch-thick industrial-board insulation.

Based on energy costs of $10.00/mcf, the total annual cost to operate each tank is as follows (certified audits are available upon request):

Uninsulated = $22,398.00
Insulated = $1,050.00
Savings = $21,348.00 per year, per tank.


Thermcraft Incorporated is an example of a company that relies on graded-insulation products provided by GIS for their new and reconditioned furnaces. Graded insulation is designed for the specific design and temperature of an application.

Thermcraft manufactures laboratory and industrial furnaces, high-temperature heaters and other thermal-processing equipment including ovens, temperature sensors, controls and diffusion heaters for a wide range of global industries including ceramic and semi-conductor.

Furnaces such as the bottom-loading elevator-hearth furnace (pictured) use the graded insulation supplied by GIS. Other furnaces such as the gas-fired car bottom, rotary-hearth, walking beam and mesh-belt conveyor furnaces are all part of the Thermcraft product line.