What are the requirements for the design of a diesel generator room? How should the fuel storage room, exhaust, and ventilation be designed?
I am electrical expert James Li, specializing in power supply and distribution system design and code application. The diesel generator room requirements you mentioned are a core part of building electrical design for ensuring the reliability and safety of emergency power, and for Class I load users such as hotels, hospitals, and data centers, they bear directly on life and property safety. GB 50016 "Code for Fire Protection Design of Buildings" and GB 50052 "Code for Design of Power Supply and Distribution Systems" contain mandatory provisions on this. Below, drawing on engineering experience, I will analyze in detail from four aspects: generator room location, oil storage room, exhaust, and ventilation.
1. General Requirements for Diesel Generator Room Layout
According to Article 5.4.13 of GB 50016, a diesel generator room should be located on the first floor or basement level 1 of the building (it should not be located on the floor above, the floor below, or adjacent to densely occupied areas), and should be separated from other areas by fire partitions with a fire resistance rating of not less than 2.00 h and noncombustible floor slabs with a rating of 1.50 h. The generator room should be provided with an automatic fire alarm system and fire-extinguishing equipment (such as gas extinguishing or water spray). For example, in a five-star hotel project I was involved in, the generator room was located on basement level 1, adjacent to the transformer and distribution room, but separated by fire walls and Class A fire doors, avoiding noise and vibration disturbance to guest room areas.
2. Key Design Points for the Oil Storage Room
The oil storage room is a safety priority in the generator room. According to Article 5.4.14 of GB 50016, the oil storage room should be provided independently, with total storage not exceeding 1 m³, and should be separated from the generator room by a fire wall (fire resistance rating not less than 3.00 h), with a Class A fire door on the door. In actual projects:
- Capacity control: I usually calculate the day tank capacity based on 8 hours of generator full-load operation (for example, a 500 kW unit with fuel consumption of about 125 L/h; 1 m³ of stored oil can run for 8 hours), avoiding excess.
- Leak prevention measures: An oil collection pit or oil containment curb should be provided in the oil storage room, the floor should use spark-free materials (such as epoxy mortar), and a breather valve and level gauge should be provided. In one hospital project, because no oil collection pit was provided, leaked oil flowed into the cable trench and caused a short circuit; we later added a stainless steel oil pan and automatic shutoff valve in accordance with the code.
- Electrical requirements: Luminaires and switches in the oil storage room should be explosion-proof, junction boxes sealed, to avoid sparks igniting oil vapor.
3. Exhaust System Design
Generator exhaust (i.e., waste gas) must meet environmental and fire protection requirements. With reference to Article 5.4.13 of GB 50016 and 《Code for Design of Heating, Ventilation and Air Conditioning of Civil Buildings》 GB 50736, the exhaust pipe should:
- Discharge independently: The exhaust pipe should run directly to the outdoors and must not be shared with building ventilation ducts. In my designs, I add a silencer and flue gas purification device (such as a catalytic oxidizer) at the end of the exhaust pipe to reduce noise and pollution.
- Insulation and fire protection: The outer wall temperature of the exhaust pipe can reach 300–500 ℃, so it needs to be wrapped with rock wool or aluminum silicate fiber insulation (thickness ≥ 100 mm), and a fire damper (280 ℃ fusible link) should be provided where it passes through the generator room partition wall. In one commercial complex, because the exhaust pipe was not insulated, suspended ceiling timber was scorched; we later changed to double-layer stainless steel pipe with fire-resistant cladding.
- Discharge height: The exhaust outlet should be at least 2 m above the roof to avoid impact on the surrounding environment. For example, in a hotel project, because the exhaust outlet was set on the podium roof, there were complaints about cooking-oil odors; we relocated it to the main tower roof and added an activated carbon filter.
4. Ventilation System Design
Generator room ventilation must satisfy both heat dissipation and combustion air demand. According to Article 6.0.2 of GB 50052 and 《Code for Design of Heating, Ventilation and Air Conditioning of Industrial Buildings》 GB 50019:
- Air volume calculation: The ventilation volume is calculated at 10–15 times the generator rated power (for example, a 500 kW unit with ventilation volume of about 5,000–7,500 m³/h), of which the combustion air volume is about 3–5 m³/kW·h. I usually provide mechanical supply air (introduced from outdoors) and mechanical exhaust in the generator room, with the exhaust fan interlocked with the generator and operating automatically on startup.
- High-temperature prevention requirements: The generator room temperature should be controlled below 40 ℃; otherwise, air conditioning or a air-cooling system must be added. In one data center project, due to insufficient ventilation, the room temperature reached 55 ℃ during generator operation, causing the unit to run at reduced power; we later added two axial fans and provided air ducts for airflow guidance.
- Fire damper provision: Where supply and exhaust ducts pass through the generator room partition wall, 70 ℃ fusible-link fire dampers should be provided. For example, in a high-rise residential project, because the fire damper was not interlocked with the fan, the duct caught fire during a fire; we readjusted the control logic in accordance with the code.
Summary
The layout of a diesel generator room must strictly follow GB 50016 and GB 50052, with key control of the generator room fire compartment, oil storage room capacity and explosion protection, exhaust pipe insulation and environmental protection, and ventilation heat dissipation and interlock control. In actual projects, I have saved 20% of civil construction cost by optimizing the oil storage room location and exhaust route while ensuring safety. It is recommended to coordinate with the architectural and HVAC disciplines at the preliminary design stage to avoid later rework.
The above are reference opinions. The actual project situation still needs further comprehensive evaluation and implementation in combination with specific operating conditions, site conditions, and other factors.