High Density Arc and Heat Resistant Cement Boards (Asbestos)

INSEAL density arc and heat resistant boards are manufactured from raw asbestos fibre and special grades of cement.

Below are a list of properties exhibited by High Density Boards

  • Good alkali and high arc resistance
  • Low conductivity and high thermal insulation
  • Able to withstand high frequencies and suitable as a fire check barrier
  • Easily machinable without splitting or chipping
  • Available in high thickness blocks of up to 100mm leading to easy manufacturing components

InSeal’s High Density Arc and Heat Resitant Cement Boards have a number of applications

  • Can be used as guide strips or splash boards in handling molten metals on hot castings
  • For transportation of hot metal and pot line insulation in aluminum industry
  • Arc chutes and deflector plates on air-break circuit breakers, contractors and fuse gear
  • Fire barrier for check doors
  • Insulation of coils, as top plate or support block in induction furnaces

InSeal’s Cement Boards are available in two grades

  • Treated
  • Untreated

Mechanical Properties for Untreated Grade

PROPERTIES   UNITS
Nominal thickness(mm)
3.0-5.0 6.4-12.5 over 12.5
Density (Nominal) gms/cc
1.95 1.95 1.95
Tensile Strength ( min. ) kgf/cm2
200 190 180
Shear Strength ( min. ) kgf/cm2
400 380 350
Flexural Strength ( min. ) kgf/cm2
450 410 350
Ultimate Crushing Strength ( min. ) kgf/cm2
1500 1400 1250
Compression Yield ( max. ) %
5 4 3.5
Water Absorption ( max. ) %
15 14 13

Electrical Properties

PROPERTIES UNITS Nominal thickness(mm) 3.0 – 5.0 6.4-12.5 OVER 12.5
Dielectric Strength in Air@90oC (min.) kv/mm 1.7 1 0.8
Dielectric Strength in Air@90oC (min.) kv >10 >10 >10

Thermal Properties

PROPERTIES UNITS
Nominal thickness(mm)
3.0-5.0 6.4-12.5 over 12.5
Carbon Arc Test Secs.
120 120 120
Spirit Burner Test DOES NOT IGNITE
Thermal Conductivity kcal/mh oC
0.6 0.6 0.6
Continuous Temp. Usage oC
350 350 350