GB18985-2021
Amount of supply gases for divers
潜水员供气量
GB 18985-2021 is a current mandatory Chinese national standard for Amount of supply gases for divers. It appears in the Machinery compliance cluster with a product safety focus and has an implementation date of Nov 1, 2021.
Applicability depends on product scope, certification route, competent authority notices and transition rules. Requst for the translation or verify source before using this record in a compliance decision.
Compliance overview
Scope and applicability
This standard specifies the supply gas flow rates and gas reserve requirements for diving operations. It applies to divers using ventilated, surface-supplied demand, and self-contained diving equipment for air diving, mixed gas diving, bounce diving, and saturation diving. It is essential for organizations planning or executing underwater engineering and commercial diving operations in China. Referenced standards include GB 26123 and GB 28396.
Technical requirements
The standard outlines the minimum supply gas flow rates required for divers during underwater operations. It categorizes requirements based on the type of diving equipment used, such as ventilated, surface-supplied demand, and self-contained diving apparatuses, factoring in varying labor intensities. For gas reserve quantities, the standard provides calculation methods for different diving profiles. This includes reserves for air diving and mixed gas diving, covering operational gas volumes, surface decompression requirements, and therapeutic gas reserves for treating decompression sickness. Specific requirements are detailed for bounce diving and saturation diving operations. Engineers must calculate reserves for establishing and maintaining saturation habitats, excursion diving, and final decompression. The standard also defines parameters for metabolic oxygen supplementation and helium recovery systems. Informative annexes provide reference data for oxygen consumption, CO2 production, and ventilation rates under different labor intensities (Appendix A). They also include tables for the upper and lower limits of oxygen concentration in heliox mixtures (Appendix B) and therapeutic gas concentrations (Appendix C).
Testing methods
This standard primarily utilizes mathematical calculation methods rather than physical testing to determine gas requirements. Key evaluation procedures include calculating minimum gas flow rates based on depth and labor intensity, and determining total gas reserves by applying safety constants (e.g., K1, K2, K3) to the sum of operational, decompression, and therapeutic gas volumes.
FAQs
What types of diving operations are covered under GB 18985-2021?
It covers air diving, mixed gas diving, bounce diving, and saturation diving using ventilated, surface-supplied demand, and self-contained diving equipment.
Are there significant updates from the previous GB 18985-2003 version?
Yes, the 2021 version introduces calculations for bounce diving, adds therapeutic oxygen and mixed gas calculations, and updates the calculation methods for saturation diving excursion gas and backup therapeutic gas.
Does the standard provide specific gas mixture ratios?
While the main text focuses on calculation formulas, the informative annexes provide reference tables for oxygen concentration limits in heliox mixtures for both diving and therapeutic purposes.
The summary above provides a high-level overview of GB 18985-2021. To ensure complete compliance for your diving operations in the Chinese market, a precise and professional translation of the full technical specifications is essential. Purchase our high-quality English translation of GB 18985-2021 today to access all detailed calculation formulas, safety constants, and reference tables.
Applicability hints
- Type
- Safety
- CCS
- R53
- ICS
- 03.220.40
- Competent department
- Ministry of Transport
- Technical committee
- Ministry of Transport
Relationships
Replaces:GB 18985-2003