320m³ Zone2 ExdⅡBT4 Low-Temperature Explosion-Proof Cold Storage | Yunnan Zhengbang Chemical Project

Project Overview

This full turnkey explosion-proof cold storage was customized for Yunnan Zhengbang Technology, a local fine chemical manufacturer, specially for sealed storage of flammable PVC emulsion, VAE adhesive and low-temperature hazardous intermediates. The warehouse belongs to Zone2 explosive gas hazardous area, all electrical & structural components reach ExdⅡBT4 explosion-proof grade, fully adapted to Yunnan plateau large day-night temperature difference and low air pressure environment.

Core Basic Project Information

• Client: Yunnan Zhengbang Technology (Fine chemical production enterprise)
• Total effective storage volume: 320 m³ | Construction floor area: ~100 ㎡ | Net height: 3.2 m
• Constant storage temperature range: -20℃ ~ -32℃ stable low temperature
• Explosion risk zone classification: Zone2 (secondary volatile release source)
• Full compliance standard: GB 50058-2014, GB 50072-2021, GB3836 explosion electrical specification

Construction cycle: 30 calendar days, signed construction Oct 17 2022 & full delivery

Pre-Construction Client Safety Pain Points

1. Original ordinary storage room without full explosion-proof certification, VAE emulsion volatile gas easily accumulates, annual safety supervision hidden danger rectification records;
2. Common thin insulation panels lead severe cold leakage, unit long-term overload, high monthly power consumption;
3. No flammable gas real-time linkage alarm system, no automatic ventilation & power-off protection mechanism;
4. Ground without anti-static copper mesh laying, static discharge easily ignites mixed volatile gas;
5. Incomplete explosion-proof acceptance documents, unable to pass annual emergency management bureau inspection.

1 Explosion-Proof Warehouse Envelope & Insulation System (Yunnan Plateau Customized)

Adopt 5-sided full closed explosion-proof structure, all joints filled with flame-retardant sealing glue to eliminate cold bridge and gas leakage points, fully match plateau large temperature difference climate:

Structural Component	Full Explosion-Proof Specification	Mandatory Safety Standard
Wall & Ceiling PU Panel	200mm B1 flame retardant polyurethane, double 0.8mm SUS304 stainless steel inner surface, λ=0.020 W/m·K	Zone2 warehouse minimum insulation thickness for -32℃ low temp
Floor Insulation	4 layers staggered 50mm XPS extruded board + full conductive copper mesh anti-static layer	Whole warehouse grounding resistance ≤4Ω
Explosion-Proof Sliding Door	Double stainless steel sandwich panel, built-in emergency inner release lock, explosion-proof hinge fittings	Staff escape safety requirement
Whole Warehouse Explosion Grade	Full set ExdⅡBT4 certified panels, electrical & pipeline fittings	Meet flammable emulsion storage Zone2 standard

Core plateau optimization: Double-layer vapor barrier laid on roof to block Yunnan daytime strong solar heat infiltration, avoid unit continuous overload operation in summer.

Mandatory structural index: Explosion vent area ≥0.05 ㎡ per cubic meter warehouse volume for pressure relief protection.

2 Full Redundant Explosion-Proof Refrigeration System

All compressors, evaporators, valves adopt full explosion-proof certification, forbidden electric heating defrost (eliminate ignition source risk), match one-operation one-standby evaporator layout:

Core Equipment Configuration

1. Main Compressor Unit: Bitzer Germany + Refcomp Italy explosion-proof semi-hermetic air-cooled condensing units (2 sets total)
2. Evaporator: LU-VE full explosion-proof low-temperature air coolers, 1 running + 1 standby design
3. Defrost Mode: Hot gas circulating defrost only, no electric heating strip inside warehouse
4. Refrigerant: Non-flammable low-temperature refrigerant, pipeline 100% welded pressure test
5. System safety highlight: Independent outdoor machine room isolated from hazardous Zone2 area, avoid high-temperature unit surface contacting volatile gas.

3 PLC Intelligent Explosion-Proof Control & Gas Interlock Safety System

Outdoor weatherproof explosion-proof control cabinet, all signal lines adopt intrinsically safe IS barrier modules, realize three-stage gas concentration automatic linkage protection:

1. Core Hardware: Siemens industrial PLC + independent backup mechanical temperature controller
2. Multi-level Alarm: Local sound-light alarm + mobile SMS remote notification
3. VOC Gas Three-Stage Interlock Mechanism

• • Gas concentration reach 20% LEL: Auto start explosion-proof ventilation fans
  • Gas concentration reach 40% LEL: Automatically cut all internal warehouse non-intrinsic safety power supply
  • Gas concentration reach 60% LEL: Full site emergency alarm trigger

4. Data Storage: 5-year non-editable temperature & gas concentration log for safety supervision inspection

4 Full Set Acceptance & Delivery Documents For Safety Supervision

Complete file package handed over after commissioning for annual emergency bureau audit:
1. All equipment ExdⅡBT4 explosion-proof certification, CCC electrical certificates
2. Warehouse anti-static grounding resistance test report (full surface ≤4Ω)
3. 72h full-load low-temperature stable operation test record
4. Flammable gas linkage ventilation & power-off simulation test report
5. Cold bridge sealing & warehouse air tightness pressure test data
6. Complete URS user requirement, SAT site acceptance test protocols

5 Measurable Post-Operation Safety & Economic Benefits

After 18 months stable operation:
1. Completely eliminate flammable gas explosion hidden danger, passed 2 consecutive annual emergency management bureau safety inspection without rectification;
2. 200mm thick full insulation + plateau heat insulation design cut annual refrigeration power consumption by 24%;
3. Full automatic gas interlock system reduce daily manual safety patrol labor cost;
4. Standardized IBC barrel zoning storage avoid emulsion leakage cross-contamination loss.

6 6 Common Hazardous Chemical Explosion-Proof Cold Storage Safety Pitfalls

1. Omit anti-static copper mesh floor → static spark ignites volatile emulsion gas
2. Adopt electric heating defrost inside warehouse → high-temperature ignition source violates GB50058
3. Allocate ordinary non-explosion fan & lighting in Zone2 area → direct safety inspection failure
4. No flammable gas three-stage linkage ventilation system → gas continuous accumulation risk
5. Thin insulation panels for -32℃ low temp → unit long-term overload frequent breakdown
6. Missing explosion vent pressure relief structure → explosion shock cannot be released safely

7 FAQ For Chemical Enterprise Safety & Infrastructure Managers

Q1 What explosion grade is required for storing PVC/VAE flammable emulsion?

A Warehouse internal belongs to Zone2 secondary volatile release area, all structural and electrical components must reach ExdⅡBT4 full explosion-proof grade complying GB 50058 standard.

Q2 Why electric heating defrost is forbidden in hazardous chemical cold storage?

A Electric heating strip will form high-temperature ignition source; once emulsion gas concentration reaches explosion limit, fire or explosion accident will occur, only hot gas defrost is allowed.

Q3 What grounding standard must the anti-static floor meet?

A Whole warehouse conductive copper mesh connected to unified grounding pile, overall grounding resistance controlled below 4Ω to eliminate static accumulation.

Q4 What documents need to be reserved for annual safety supervision inspection?

A Full set explosion-proof equipment certificates, anti-static ground test records, gas interlock simulation test reports, 72h full-load temperature operation data logs.

Q5 Does Yunnan high altitude need special cold storage insulation design?

A Yes, strong solar radiation and large day-night temperature difference require double-layer roof vapor barrier + 200mm ultra-thick B1 PU panels to reduce summer unit overload power consumption.

Custom Hazardous Chemical Explosion-Proof Cold Storage Inquiry

If you need Zone2/Zone1 low-temperature explosion-proof cold storage design for fine chemical, adhesive & emulsion factories in Yunnan, Guizhou and Southwest plateau regions, provide storage chemical flash point & target temperature to get free layout drawing and full explosion-proof compliance quotation.

Construction & Completion Photos