1. Evolution of Regulatory Classification
1.1 Early Classification (1981–2016)
The earliest relevant regulation dates back to the Safety Supervision Regulation for Pressure Vessels (Labour and Boiler Regulation No. 7 [1981]).
Article 80 explicitly classified pressure gauges alongside safety valves as “safety accessories”, requiring periodic verification at least once a year. This classification placed pressure gauges in the same category as safety valves and rupture discs, highlighting their critical role in special equipment safety.
1.2 Current Classification Adjustment (TSG 21-2016)
In 2016, the Supervision Regulation on Safety Technology for Stationary Pressure Vessels (TSG 21-2016) redefined safety accessories.
According to Clause 1.5, pressure gauges were reclassified as “safety protection devices”, rather than direct action “safety accessories” such as safety valves. As protection devices, pressure gauges primarily perform monitoring functions, relying on human or automated responses to ensure safe operation.
1.3 2024 Draft Regulation Update
The draft revision of the Supervision Regulation on Safety Technology for Stationary Pressure Vessels (2024, public consultation) maintained the classification of pressure gauges as “safety protection devices”, with unchanged verification requirements and intervals. This retained the core framework introduced in TSG 21-2016.
2. Comparative Management Requirements
| Aspect | Safety Accessories (Pre-2016) | Safety Protection Devices (Current) |
|---|---|---|
| Regulatory Definition | Direct-acting components for pressure relief and isolation | Monitoring devices triggering human/system response |
| Verification Cycle | At least once per year | At least once per year |
| Failure Handling | Immediate replacement/repair | Immediate replacement/repair |
| Legal Basis | Early regulations (1981–2016) | TSG 21-2016, draft 2024 regulation |
Note: Despite the reclassification, the management requirements for pressure gauges remain strict, particularly in verification intervals and failure handling.
3. Typical Enforcement Cases
Case 1 — Jiangsu Province
A chemical company was fined 50,000 RMB by the Xuzhou Market Supervision Administration for operating a safety protection pressure gauge beyond the required verification interval (over 9 months overdue).
The penalty cited violation of Article 25 of the Metrology Law, which mandates verification of safety protection devices.Case 2 — Shandong Province
A pressure vessel manufacturer was ordered by the Shandong Special Inspection Institute to recall vessels equipped with unverified pressure gauges, in violation of Clause 9.1.1 of TSG 21-2016. The company was required to perform re-verification and compliance checks before re-delivery.
Key Insight: Reclassification does not diminish the legal and safety importance of pressure gauges—non-compliance can trigger severe administrative penalties.
4. Compliance Management Recommendations for Enterprises
4.1 Establish a Classification Management List
Enterprises should classify pressure gauges by function and application scenario, ensuring clear regulatory compliance mapping.
Example classification:
Production Safety Monitoring: Critical process gauges on pressure vessels and pipelines.
General Process Monitoring: Non-critical auxiliary gauges, still subject to metrology verification.
IoT-based Smart Gauges: Conforming to GB/T 34049 standards, connected to monitoring platforms.
4.2 Adopt Digital Management Tools
Leverage IoT-enabled pressure gauges and provincial special equipment platforms (e.g., Zhejiang “Special Equipment Online”) for:
Remote monitoring
Automatic verification reminders
Data archiving and compliance reporting
This reduces manual management costs and enhances equipment safety.
5. Conclusion
Although the classification of pressure gauges has shifted from “safety accessories” to “safety protection devices,” their role in ensuring the safe operation of special equipment remains critical.
Strict adherence to current regulations, timely verification, and structured classification management are essential to avoid compliance pitfalls.
Integrating digital monitoring solutions can further enhance management efficiency, reduce human error, and safeguard enterprise operations against regulatory risks.