Views: 0 Author: Site Editor Publish Time: 2026-06-17 Origin: Site
This is not a product brochure. This is a checklist for you – the site preparation work you should complete in parallel while your CNG integrated secondary filling station is being manufactured or is in transit. No vague suggestions – everything here can be directly confirmed with your site engineer.
1. Foundation & Ground
The bottom line: No large concrete foundation is needed, but safety clearances are the absolute red line.
Preparation Item | Specific Requirement | Verification Method / Basis |
Site Selection | Must meet external safety clearances. Distances from the equipment to important public buildings, civil buildings, open flames, etc., must comply with national standards. | Check distances one by one (equipment is equivalent to "gas storage well, gas dispensing equipment, compressor"). Example: distance to important public buildings must not be less than 30 m. |
Ground Type | Compacted ground is sufficient. The equipment is skid-mounted; the frame distributes the load. | Verify that the ground bearing capacity meets the static load requirement. |
Anchor Bolts | Not needed in general – the skid frame sits directly on the ground. However, according to standards, crash barriers (≥0.5 m high) must be installed on the side of the fixed gas cylinder group adjacent to the station's vehicle lane and on the vehicle approach side of the dispenser. | Coordinate with your civil engineer on wind/seismic requirements and arrange for crash barrier installation. |
Drainage | No standing water allowed in the equipment area. | The lowest point of the site should be lower than the equipment base elevation. |
Key additional points:
1. Safety distance is the prerequisite: Before leveling the ground, you must confirm that the site meets the code requirements. This is the foundation of everything. Violation cannot be corrected later. The mandatory provisions of the code strictly enforce this.
2. Crash barriers are not optional: As per national mandatory requirements, crash barriers must be installed on the vehicle-adjacent side of fixed gas storage cylinders and at the vehicle approach side of dispensers. This is to protect critical equipment in case of vehicle collision.
2. Electrical Power Supply
The secondary station's compressor is a motor-driven hydraulic system. What you need to prepare:
Preparation Item | Description | Basis |
Three-Phase Power | Match motor power to the selected flow model (500/1000/1200/2500 Nm³/h). Confirm that local grid voltage/frequency is within the equipment's rated range. | Motor drives hydraulic pump; standard industrial three-phase. |
Distribution Cabinet | Route a dedicated circuit from the main distribution cabinet to the secondary station's reserved connection point. Cable size should include a 20% margin over the equipment's rated current. | Avoid voltage drop caused by sharing a circuit with other high-power loads. |
Backup Power | If a generator is not integrated, reserve an ATS interface for future connection. | Ensure refueling operations can continue during a power outage. |
Grounding System | Must complete lightning protection and static electricity grounding system according to standards. | National code mandates: steel gas storage cylinders must have lightning protection grounding with at least two grounding points. Grounding resistance must not exceed 10 Ω. |
Key reminder: Do not wait until the equipment arrives to think about grounding. The grounding grid is a permanent site facility that must be installed in advance and inspected by the local lightning protection center. All grounding systems (lightning, working, protective, static) should preferably share a common grounding device.
3. Site Space
Area | Dimensions / Description | Notes |
Equipment Body | 12.2 m × 2.4 m (40 ft footprint) | Contains the cabinet itself, not including surrounding operation and safety space. |
Front Operation Aisle | At least 3–4 m | Dispenser operation front; vehicle parking for refueling. |
Trailer Unloading Side | Leave 13–15 m on the gas inlet side | A CNG tube trailer (with tractor) needs room to fully extend and turn. |
Vehicle Passage Area | Space for refueling vehicles to enter, exit, and turn around. | Plan for a vehicle queue buffer. Estimate number of lanes based on peak daily vehicle count. |
Vent Stack Setup | Must reserve safe venting space. The vent stack outlet has safety clearance requirements to external buildings; the vent pipe should be vertical and elevated above surrounding structures. | The location and height of the vent must comply with standards to ensure safe dispersion of leaked gas. |
Space supplement: In addition to normal traffic space, reserve sufficient room for the CNG vent stack installation and its safety zone. No area for prolonged personnel stay should be near the vent outlet.
4. Environmental Adaptability (Compliance & Safety Requirements)
This section clarifies the "mandatory items" required by standards versus the "built-in items" of the equipment.
Your Concern | What You Actually Need to Prepare (Beyond Built-in Equipment Features) |
Do I need a station building? | Consider the emergency shut-off valve installation location. Standards require manual and automatic shut-off valves on the incoming natural gas pipeline. If installed outdoors, consider freeze protection, theft prevention, and easy operability. |
Lightning/Static Protection | Must complete grounding grid construction. The equipment has grounding terminals built-in, but you need to install the grounding grid in advance. This is mandatory. |
Explosion Hazardous Area | Must clearly define the boundaries of the explosion hazardous area. National code appendices define the scope. All electrical equipment within this area must be explosion-proof; no non-explosion-proof electrical connections are allowed. |
Noise Complaints | Equipment has built-in noise reduction, but you still need to meet local environmental noise standards. |
Core message: The equipment's built-in rain protection, noise reduction, temperature adaptability, etc., are product features. But the lightning grounding grid, vent stack installation, layout meeting safety clearances, and explosion area control are mandatory tasks that you must complete according to codes and local requirements – they cannot be avoided.
5. Gas Inlet and Outlet
Preparation Item | Requirement |
Gas Source | CNG tube trailer (CNG transported from mother station). Prepare high-pressure flanges or quick-connect couplings at the secondary station side. |
Tube Trailer Parking | The tube trailer must park on the inlet side of the secondary station. Note: The fire separation distance from the fixed parking position of the storage tube trailer to external buildings must be determined according to the distances for gas storage cylinders. |
Gas Outlet | The secondary station comes with its own dispenser. But crash barriers (min. 0.5 m high) must be installed near the dispenser. |
Pneumatic & Hydraulic System | Standards require the hydraulic equipment to have overpressure protection for the hydraulic oil and a system that automatically shuts down the hydraulic pump and alarms when gas leakage is detected. These are built into the equipment, but test interfaces should be accessible on site. |
Supplement: When planning the unloading area, also consider the safety distance of the unloading point. The requirements for unloading points at other types of filling stations can be referenced analogously – CNG unloading points also need to maintain safe distances from other facilities and equipment within the station.
Reference: Typical parameters of a common CNG secondary filling station (non-brand-specific)
Parameter | Specification |
Flow Rate | 500 / 1000 / 1200 / 2500 Nm³/h |
Compressor Type | Hydraulic reciprocating (or mechanical reciprocating), two-stage compression |
Inlet Pressure | ≤ 25 MPa |
Max Working Pressure | 25 MPa |
Skid Footprint | Approx. 12,192 × 2,438 × 1,400 mm (universal skid size) |
Cabinet Material | Stainless steel / painted cold-rolled steel (optional) |
Type Approval Certificate | Mandatory – the manufacturer, model, and design pressure stated on the certificate must match the delivered equipment. |
Component Certification | Key components (safety valves, pressure gauges, CNG piping, etc.) must have relevant certifications (e.g., special equipment manufacturing license). |
Summary: Four Things You Must Do – Then Your Site Is Ready for the Equipment
Looking back at this checklist, based on national codes, the secondary station site preparation is actually four things you must accomplish:
1. Compliance Confirmation: The site selection, safety clearances, vent stack arrangement, and explosion hazardous area classification must all comply with national standards.
2. Infrastructure Construction: ① Compacted ground; ② Completed and tested lightning/static grounding grid; ③ Three-phase power wiring in place.
3. Space & Safety Facilities: ① Reserve space for the equipment, tube trailer, and refueling vehicles; ② Install crash barriers; ③ Reserve vent stack location.
4. Connection Conditions: ① Align the tube trailer unloading point with the interface; ② Verify the equipment's type approval certificate and other qualification documents.
Everything else – rain protection, noise reduction, generator set, PLC remote monitoring, safety shut-off valve interlock – is already solved by the manufacturer before delivery. No on-site assembly or commissioning is needed.
If you are preparing a project, send this checklist to your site engineer. If you are unsure about any item (like specific electrical interface locations or space limitations for access), you can contact your supplier via WhatsApp or inquiry to get the outline drawing and wiring diagram before the equipment is shipped, so you can prepare the site in advance.
