Hazardous-Area Classification Design for Semiconductor Fabrication Facilities: Based on FM1-44, DLC and National Standards

FM1-44 DLC Semiconductor Factory Explosion-Zoning Design: Requirements Based on FM and National Standards

With the rapid development of the semiconductor industry, factory safety design—especially the planning and implementation of explosion-hazard zoning—has become a topic of great concern in the industry. This article will examine in detail the core elements of explosion-zoning design for semiconductor factories, with particular analysis of the design requirements and practices for explosion-venting fasteners, tethering cables, fire-and-blast-resistant walls, and fire-and-blast-resistant doors, providing the industry with a comprehensive and professional reference.

• Explosion venting design

Explosion venting design is an indispensable part of the explosion protection system, requiring precise calculations and systematic considerations. According to the FM1-44 standard, GB55037 building fire protection code, and practical application experience, explosion venting design should focus on the following key elements:

• Base venting pressure value: 0.96 kPa

• Venting panel weight limits:

  FM1-44 recommendation: not exceeding 3 lb/ft2 (14.6 kg/m2)
  Considering fire-resistance time requirements: allowed up to 8 lb/ft2 (39 kg/m2)

• Wind speed factor: adjust according to FMRoofNav calculation results

• Fire-resistance time requirements:

  Explosion-venting wall (non-load-bearing exterior wall): 1 hour fire-resistance time
  Explosion-venting roof: 0.5 hour fire-resistance time

1. Material selection and application

• Rock wool sandwich insulated color steel panels: used in conjunction with explosion-venting fasteners; currently a common FM-certified explosion-venting roof and wall solution domestically.
  • Advantages: significant cost-effectiveness, mature waterproofing technology, high versatility, easy installation.
  • Application: suitable for large-area roofs and exterior walls for venting design.
  • Fire performance: products can be selected to meet 1-hour (walls) or 0.5-hour (roofs) fire-resistance time requirements.
• Explosion-venting fasteners: combined with rock wool sandwich insulated steel panels to ensure effective pressure release in the event of an explosion.
  • Components: include venting washers, venting screws, positioning sleeves.
  • Technical specifications:
    • Venting washer failure force: standard value 700 N, FM certified.
    • Venting static pressure design range: 0.96–1.92 kPa.

Note:

1. When the venting area is insufficient, additional venting doors and windows can be added to meet national standards and FM requirements.

2. Designing full-face venting windows is not recommended because of high cost and tendency to leak, resulting in high maintenance costs.

3. Wind speed considerations

When determining the venting pressure value, local wind speed conditions must be combined to avoid damage to venting structures in extreme weather:

1. Calculate local wind pressure values according to FMRoofNav and GB50009 Code for Design of Building Structures.

2. Choose the larger value as the minimum design parameter.

3. Tethering cable design

Tethering cables are used to prevent venting panels from completely detaching in an emergency. FM1-44 specifies the arrangement and structural practices for tethering cables as follows:

• Material: SUS304 stainless steel.
• Specification: diameter 6 mm, length 900 mm, break load exceeding 20 kN.
• Arrangement: use two steel cables for each panel section 3 ft (0.9 m) wide and 15 ft (4.6 m) high, differing from the national standard arrangement of placing them at both ends of the panel material.

4. Fire-and-blast-resistant wall design

• Material: recommended to use composite steel plates to meet both fire and blast requirements.
• Fire performance: CNAS certified, fire-resistance time not less than 4 hours, blast resistance not less than 300 kPa.
• Blast design:
  • Structural keel design pressure not less than 4.8 kPa.
  • Structural design must simultaneously meet the dynamic structural calculation requirements of FM1-44 and GB50779 standards, and provide calculation documentation.

5. Fire-and-blast-resistant door design

• Material: recommended to use composite blast-resistant steel plates, combining fire and blast resistance.
• Fire-and-blast performance: can achieve Class A 1.5-hour fire-resistance time and pass CNAS explosion test certification.
• Blast design: design pressure not less than 300 kPa.

6. Fire-and-blast-resistant rolling shutter door design

• Material: recommended to use steel plates to meet fire and blast requirements.
• Fire-and-blast performance: can achieve Class A 3-hour fire-resistance time and pass CNAS explosion test certification.
• Blast design: design pressure not less than 1000 kPa.

Conclusion

Explosion-zoning design for semiconductor factories is a technically complex and critically important task. By precisely designing explosion-venting fasteners, tethering cables, and fire-and-blast-resistant walls, and by strictly following FM Global and national standard requirements combined with the latest composite steel plate technologies, the overall safety performance of factories can be greatly improved. At the same time, the design process needs to balance venting and fire-resistance effects to choose the most appropriate solution. As an industry-leading provider of integrated fire and zoning solutions, Shanghai Tengxi Construction Engineering will continue to devote efforts to providing safer and more reliable explosion-protection solutions for the semiconductor industry, promoting the safety development of the industry.