Fire-Rated Duct Materials EI45 – EI120: Classification & Applications
In ventilation and air conditioning (HVAC) systems – especially in projects with strict fire protection requirements (PCCC) – the use of EI-rated fire-resistant ducts is mandatory according to regulations. These ducts not only ensure effective fire resistance and thermal insulation but also require specific materials corresponding to fire resistance durations such as EI45, EI60, EI90, or EI120.
So, what materials are used in EI45 – EI120 fire-rated ducts? Let’s explore in detail with Eusteel below.
1. What Is an EI Fire-Rated Duct?
An EI fire-rated duct is an air duct system designed with the following capabilities:
- Prevent flame penetration (E – Integrity)
- Prevent heat transfer (I – Insulation)
The EI rating (e.g., EI60, EI90, EI120) indicates the duration for which the duct can withstand fire and heat exposure without structural failure or exceeding allowable heat transfer limits.
2. Material Classification of EI45 – EI120 Fire-Rated Ducts
2.1. Duct Core
- Galvanized steel (GI): Commonly used, thickness from 0.75mm to 1.2mm
- Stainless steel (SUS 304, SUS 430): Used in highly corrosive environments such as chemical or food processing plants
2.2. Fire-Resistant Insulation Layer
Depending on the fire rating, insulation materials vary as follows:
| EI Rating | Main Insulation Material | Standard Thickness |
|---|---|---|
| EI45–EI60 | Mineral wool (250–600°C) | 25–30 mm |
| EI90 | Ceramic fiber (800–1000°C) | 30–40 mm |
| EI120 | High-grade ceramic fiber or intumescent coating | ≥ 50 mm |
2.3. Outer Protective Layer (Cladding)
- Galvanized steel / steel mesh: Secures the insulation layer
- Silicone-coated fiberglass / aluminum foil: Provides waterproofing and improves aesthetics
- Intumescent coating: Expands under high temperatures to enhance fire protection
3. Material Configuration by EI Rating
| EI Rating | Material Composition | Application |
|---|---|---|
| EI45–EI60 | GI steel + mineral wool | Residential buildings, small offices |
| EI90 | GI steel / stainless steel + ceramic fiber | Apartments, commercial centers |
| EI120 | Stainless steel + high-grade ceramic fiber + intumescent coating | Factories, chemical warehouses, basements, high-rise buildings |
4. Installation Requirements
When installing EI fire-rated ducts, the following must be ensured:
- Install fire dampers at wall and floor penetrations
- Use heat-resistant gaskets at joints to prevent air leakage and fire spread
- Support ducts with fire-resistant hangers or structural frames
- Comply with fire resistance testing standards such as EN 1366 or TCVN 9311-1
5. Eusteel EI45 – EI120 Fire-Rated Ducts
At Eusteel, we manufacture and supply fire-rated ducts from EI45 to EI120, meeting all technical standards and fire certification requirements. Our experienced engineering team provides tailored material solutions based on project conditions and budget.
