What’s The Difference Between TP(a) And TP(b) Diffusers?

October 13, 2023

In the world of lighting technology, the terms TP(a) and TP(b) are often used to assess and categorise luminaires and lighting fixtures. These designations play a crucial role in ensuring the safety and performance of lighting products. So, let’s take a closer look at TP(a) and TP(b) diffusers and how they relate to lighting.

What Are TP(a) and TP(b)?

TP(a) and TP(b), which stand for “Thermoplastic” and “Thermosetting Plastic” respectively, are classifications of materials used in the construction of lighting enclosures. These classifications are based on the flammability and heat resistance properties of the materials.

TP(a) – Thermoplastic

Thermoplastic materials are known for their ability to soften when exposed to heat and then harden as they cool. They are relatively easy to mould and shape, making them a popular choice in the lighting industry. TP(a) materials are typically used for non-fire-rated luminaires, where fire resistance is not a primary concern.

TP(b) – Thermosetting Plastic

In contrast, thermosetting plastics are designed to withstand high temperatures without softening. They undergo a chemical change when exposed to heat, making them a preferred choice for applications that require fire-resistant properties. TP(b) materials are commonly used in luminaires that need to meet specific fire safety standards.

The Importance of TP(a) and TP(b) in Lighting

The choice between TP(a) and TP(b) materials in lighting design is critical for several reasons:

  1. Fire Safety: TP(b) materials are inherently more fire-resistant, making them suitable for applications in areas with stringent fire safety regulations, such as commercial buildings.
  2. Durability: TP(b) materials are more durable and can withstand higher temperatures, which is important for fixtures that generate significant heat.
  3. Application-specific: The selection of TP(a) or TP(b) depends on the specific requirements of the lighting fixture and the environment in which it will be installed.
  4. Regulatory Compliance: Different regions may have varying regulations regarding the use of TP(a) and TP(b) materials in lighting fixtures. Understanding and adhering to these regulations is crucial.

TP(a) and TP(b) in Real-world Scenarios

Let’s explore how TP(a) and TP(b) are used in various lighting scenarios:

Home Lighting

In residential settings, where fire safety standards are less stringent, TP(a) materials are commonly used. These materials allow for cost-effective and versatile lighting fixtures suitable for a wide range of home applications.

Commercial Lighting

Commercial buildings often require lighting fixtures that meet stricter fire safety standards. In such cases, TP(b) materials are preferred due to their ability to withstand higher temperatures, reducing the risk of fire hazards.

Industrial Lighting

In industrial settings, where lighting fixtures are exposed to extreme conditions, TP(b) materials are almost always the material of choice. Their exceptional heat resistance and durability make them ideal for these environments.

Outdoor Lighting

Outdoor luminaires need to withstand the elements, and TP(b) materials excel in this regard. They are less prone to degradation from exposure to sunlight and other weather conditions.


Understanding TP(a) and TP(b) is essential for anyone involved in lighting design and installation. The choice between these materials can impact the safety, performance, and longevity of lighting fixtures. By selecting the right material for each application, you can ensure that your lighting solutions meet the required standards and regulations.