New Generation of KMAX Rigid Ducting

Schauenburg Industries Ltd. is dedicated to providing quality products to the mining and tunnelling industries. Through continued research and development we have introduced innovative improvements to the manufacturing process for our filament wound rigid pipe. We take pride in announcing the precedent setting K Factor and Air Loss results as the best in our industry.

KMAX Rigid Ventilation Ducting

Phenolic Resin: The Manufacturing Difference That Results in a Better Product

Schauenburg Industries Ltd. Rigid Ventilation Ducting is manufactured for use in mining and tunnelling applications. Schauenburg combines a filament winding process and phenolic resin for maximum rigid duct strength. One of the advantages of phenolic resin is its excellent acid resistance which is a result of the acid cure process. Because phenolic resin is water based and polyester is oil based, phenolic resin is inherently flame resistant, and no fire inhibitors are added. These inhibitors detract from the strength of polyester resins making them more brittle.

Destruction Test

  • Data was collected using a Gardner Variable Height Tester.
  • Flex strength ASTM D-790.
  • Flex Modulus ASTM D-790.
  • Greater stiffness allows higher negative pressure capability at equal weights.
Property Schauenburg Phenolic Duct Polyester Duct Interpretation
Impact Test
88 72 Ability to resist a point impact
Flex Strength (PSI)
58,619 66,6676 Load bearing strength
Flex Modulus
2325 1534 Stiffness

Advantages & Features

  • Upholds its integrity in a fire longer than metals; will operate up to 200°C while maintaining stability.
  • Fire resistant according to ASTM E-162 with flame spread index of less than 25.
  • Will not promote or sustain combustion. Thermal conductivity is much lower than metals 0.20 – 0.24 w/m/k.3. Antistatic properties 10³ ohms @ 1% wt. surface resistivity.
  • Bell/Spigot ensures a safer installation – eliminating pinch points (flanged joints are available).
  • Joints – Bell and Spigot can move 7 degrees right to left and up or down for direction.
  • Available with a flanged end. Flanges are installed prior to filament winding. Flanged minimizes leakage and provides stabilization from high shock waves during the blasting cycle. V-lock couplings speed up installation.
  • Less than half the weight of steel. For example a Rigid Oval (36×62) x 20’ = 400 lbs approximately, whereas the identical sized steel vent would be approximately 1,000 lbs.
  • Low installation cost due to lightweight pipe.
  • Joints are manufactured complete with internal rubber gaskets to prevent leakage and reduce resistance at the joints.
  • When subject to loading or impact, springs back to shape (memory), while metal will dent and leak and may start to recoil.
  • Smooth interior to guarantee low flow resistance and therefore an increase in power savings.
  • EMR/CSA and MSHA approved for underground.
  • Can withstand high positive and negative pressures.
  • Acid mine water resistant and rot proof.
  • Long service life.


  • Filament wound rigid ducting.
  • Smooth inner surface – low friction loss.
  • Joints are manufactured with internal rubber gaskets to prevent leakage
  • Tapered and straight ends for airtight joints.
  • Easy installation – guaranteed fit.
  • Strong nylon straps with D Rings for interlocking of sections
  • Suspension straps are available for added strength and safety.
  • Tapered ends specially reinforced.

Round KMAX Ducting

Round filament wound ducting is manufactured in a technically advanced process of bonding phenolic resin and fiberglass strands. Exceptionally smooth inner surface guarantees the lowest friction factor and highest volume of air. Due to its round shape and the outstanding strength Schauenburg Rigid Round Ducting withstands high positive and negative pressure and resists impacts caused by moving equipment, flying rocks and rough handling. Standard sizes range from 12” to 72” diameter. Standard lengths are 10’ and 20’ (homogeneous, no splice).


Oval filament wound ducting is an efficient way to handle todays high environmental requirements under restricted space conditions

Oval KMAX Ducting

Oval filament wound ducting is the most efficient way to handle today’s high air requirements in mine ventilation under low space conditions. The special shape and exceptionally smooth inner surface guarantees the lowest friction and highest volume of air. Oval KMax Ducting can be used for both negative and positive pressure ventilation systems. Standard sizes available from 14” equivalent (10 x 19) to 48” equivalent (36 x 62). Standard lengths are 10’ and 20’ (homogeneous, no splice). Fan adapters and fittings are also available.

New Headings

Schauenburg KMax Oval Rigid Ducting enables you to develop new headings at a reduced cost. These savings will likely pay for the total ventilation system. A lower back height will require less muck removal which will equal a reduced development cost.

Existing Drifts

The Oval Duct can be used in existing drifts and X cuts, thus allowing the operation of larger LHD equipment without reduction of air volume or clearance. The duct can be installed with the long axis horizontal, or vertical if an existing drift has a low back height.

KMax Rigid Phenolic Ducting – Fittings & Accessories

Special sizes, lengths and wall thickness available on request.

  • Fittings for all applications are fabricated from flame retardant, corrosion resistant material.
  • Elbows 22°, 30°, 45°, 60°, and 90°.
  • Flexible Elbows.
  • Tees.
  • Standard Wyes with 60° take off, 45° take off.
  • Symmetrical Wyes with 45° take offs.
  • Parallel take off Wyes and symmetrical.
  • All Wyes are available with 1 or 2 dampers.
  • Reducers and transition pieces.
  • Fan Adapters.
  • Flanged or Bell & Spigot Connections.
  • Special shapes available on request.


Suspension Hangers (straps)

Suspension Hangers (straps) are an inexpensive way to eliminate costly chain or rope and damage to ducting. They are strong and durable and can be suspended from one common hook or from 2 to limit swaying. The Suspension Hangers (straps) can be manufactured to fit any size of round or oval ducting.

KMax Ducting – Fire Resistant Phenolic Resin

Schauenburg KMax ducting is manufactured using phenolic resins. One of the main attractions of phenolic materials is its fire performance. The table below shows some typical fire test results for phenolic/glass composites and compares these to polyurethane and polyester.

Fire Properties of Phenolic/Glass Composites Compared with Polyurethane and Polyester


Property Phenolic Polyester Rigid Polyurethane
ASTM D229 – Oxygen Index 45-55* 40 20-25
ASTM D229 – Rate of burning Does not ignite
BS 476 PT.7 – Spread of Flame Class 1 (Zero Spread) Class 1 Class 1 – Class 4
Toxicity of combustion products Very low Toxic Toxic
Smoke Virtually NIL Very high Very high
* Catalyst Dependent


When phenolic resin ducting is exposed to fire they char on the surface which further protects the underlying layers from the heat source. In extreme conditions when fire does destroy the product only gasses of Carbon, Hydrogen and Oxygen are produced. This in essence means that the phenolic can only break down to form Carbon Dioxide, Water and Carbon Monoxide. These gasses will result from any form of combustion. A most significant factor is also the very low levels of visible smoke produced. See test results.

Phenolam Laminate Test Results


Test – Flammability ASTM Test Results
NBS Smoke Chamber E-622
D16 >5 min.
Dmax 42
Radiant Panel Test E-162 6.7
Tunnel Test E-84
FS1 19
Smoke 12
Limiting Oxygen Index D2863 67
Heat Deflection @ 264 psi D-648 >570°F
Linear Thermal Expansion 2.93 x 10.5 m/in. °F
Specific Heat @ 50°C 0.3 cal/ g°F


The physical properties of phenolic fiber reinforced composites are retained to at least 200°C at which temperature other matrix resins have generally degraded substantially. The inherent fire properties of phenolic resins composites are excellent having the highest fire rating in all test methods, extremely low smoke emission and virtually no toxic combustion products. E.M.R. Flame Certificate Number 395.

For more in depth information on our KMAX Ducting systems, specifications and accessories, please click below.