CPVC wood effect Siding

CPVC as a Wood Alternative

Posted by TempRite® Engineered Materials EMEA Team on 10/12/2021

CPVC as a Wood Alternative

TempRite Engineered materials specialize in polymer resins and compounds using CPVC (Chlorinated Polyvinyl Chloride.) Its inherent and flexible attributes allow for versatile product development, but not always in applications where plastic is typically expected to be applied.

CPVC can be extruded into profiles for a variety of applications where typically, product designers and architects favour wood. This strong, long lasting wood alternative offers versatility, without vulnerability:

  • Higher Flash Ignition Temperature
  • Better Flame and Smoke Properties
  • Lower Smoke Density
  • Better Flame Retardancy
  • Low Thermal Conductivity

Fire and Smoke Characteristics

The key to CPVC’s success as a wood alternative is its fire and smoke resistance.

Wood’s chain of combustion is significantly more volatile than CPVC. As volatile particles are released from the material and react with free radicals, fire is produced. Wood contains a very high concentration of volatile molecules, allowing wood to burn easily. The combustion of volatiles also produces smoke, which in the case of wood can contain a vast array of particulate matter and Volatile Organic Compounds (VOCs.)

As PVC burns, hydrochloric acid is knocked away from the polymer and becomes gas (zipper dehydrochlorination,) which reacts with free radicals to become chlorine radicals and water. Conjugated dienes are formed in the polymer, allowing crosslinking between molecules, inhibiting the breakdown of the material.

In CPVC’s case, zipper dehydrochlorination is inhibited, due to the additional chlorine atoms within the molecular chain. This process promotes crosslinking much faster, restricting volatile activity further.

All materials produce byproducts when they burn; however, CPVC produces much less smoke when compared to wood, thanks to the crosslinking forming a charred insulative barrier.


Wood vs CPVC

To explain this in terms of temperature, we only need to compare the Flash Ignition statistics of each material.

The Flash Ignition Temperature is the precise temperature at which enough volatiles have been released in order for a material to catch fire. A common misconception is that all plastics require only very low temperatures in order to burn.

Below are the Flash Ignition Temperatures of CPVC, non-chlorinated ordinary PVC, white pine and wood.

Material Ignition Flash Temperatures

As should be expected, CPVC carries a much higher ignition temperature than ordinary PVC; however, both polymers require higher temperatures to burn when compared to wood and white pine, a common building and interior design material.


CPVC as a Wood Alternative in Construction

CPVC’s inherent resistance to fire presents new opportunities to designers, using CPVC as a construction medium.

In outdoor applications, even in areas that can reach extremely high temperatures, CPVC is engineered to withstand the outdoor elements, UV in particular. CPVC is produced under intense UV light, making its resistance to UV inherent.

Heat and UV related corrosion on outdoor building materials is both common and costly; another common misconception is that thermoplastics are not prepared for this environment. CPVC is resistant to common UV related degradation such as chain cleavage, while retaining its appearance over decades.

CPVC is therefore a recommended choice as a wood alternative, or as a construction material designed to give the aesthetic of wood in a number of ways:

Siding - CPVC can be extruded to panels for outdoor construction in a wider variety of styles and colour options than wood, maintaining traditional styles but with stronger, modern materials.

Fencing - CPVC’s UV and weather protection is unmatched by wood and in most environments can support large fencing structures without costly repairs or a weathered, faded finish over many seasons.

Decking - CPVC as a safe and versatile garden material can be extruded to sturdy, weather resistant decking boards to match the style of the outdoor living space.

Fenestration - CPVC compounds are already a popular choice for window profiles and doors, offering long lasting custom designs on the inside and an additional layer of fire safety on the inside, with its natural flame retardant properties.

CPVC as a wood alternative in wood effect siding

Environmental impact of CPVC

TempRite Engineered Materials’ development of CPVC is part of an ongoing commitment to reduce adverse effects on the environment, across the manufacturing industry.

Thanks to CPVC’s innovative use of natural resources and sustainable processing methods, manufacturers can benefit from its qualities:

  • CPVC requires less energy to produce than many alternatives
  • Reduced toxicity of combustion byproducts
  • Recyclability both at manufacturing stage and at the end of the product’s life cycle

As a wood alternative, CPVC offers manufacturers advantages in a number of environmental categories:

Fossil depletion - CPVC is 67% chlorine from salt mines and therefore requires less fossil depletion in order to manufacture.

Climate change - CPVC makes less of a contribution to the conditions of our climate.

Energy consumption - CPVC requires less energy to process and manufacture.

Recyclability - Manufacturing using wood produces a lot of waste material; CPVC cutoffs can be added back into injection moulding or extrusion processors for continued productivity and minimal waste.

Talk to a TempRite Engineered Materials expert today to discuss the role of CPVC as an effective, long lasting and environmentally conscious alternative to wood in your next project.





TempRite® Engineered Materials EMEA Team

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