Interpretation of Key Clauses of GB 50015-2019
"Standard for Design of Building Water Supply and Drainage" GB 50015-2019 is the most important national standard in the field of water supply and drainage design. It was issued in June 2019 and implemented on March 1, 2020. Compared with the previous edition, the new standard has major revisions in the following aspects: (1) The pressure limit for zoning of domestic water supply systems was adjusted from 0.45 MPa to a static pressure at the lowest sanitary fixture outlet of each zone that should preferably not exceed 0.45 MPa, and the water supply pressure at the service pipe should not exceed 0.35 MPa; (2) design requirements for solar hot water systems and heat pump hot water systems were added; (3) measures to strengthen secondary pollution prevention and control of domestic drinking water were reinforced; (4) a calculation formula for the maximum design drainage capacity of domestic drainage stacks was added. Hotel designers should focus on mastering the mandatory clauses in Chapter 3 (Water Supply), Chapter 4 (Drainage), and Chapter 6 (Hot Water). The standard appendices also provide key parameters such as water use quotas and hourly variation coefficients for various building types, which are the direct basis for design calculations.
Requirements of Fire Water Supply Related Standards
Hotel fire water supply design must simultaneously satisfy multiple standard requirements. The core bases include "Technical Code for Fire Water Supply and Hydrant Systems" GB 50974-2014 and "Code for Design of Sprinkler Systems" GB 50084-2017. According to Clause 3.3.2 of GB 50974-2014, the indoor hydrant water flow rate for a Class I high-rise hotel building should not be less than 40 L/s, and the fire duration should not be less than 2 hours; the effective volume of the fire water tank should be calculated based on the fire water consumption during the fire duration and should meet the safety requirements of two-way fire water supply. According to GB 50084-2017, automatic sprinkler systems should be installed in hotel guest rooms, public areas, and corridors, with the hazard classification designed as Ordinary Hazard Class I, sprinkler density not less than 6 L/(min·m2), and operation area 160 m2. Fire pumps should be provided with standby pumps, adopt self-priming suction, and the fire control room should be able to remotely start and stop the fire pumps. The fire water supply system and the domestic water supply system must be completely independent, and shared piping is strictly prohibited.
Green Building and Water Conservation Standards
Hotel water supply and drainage design is closely related to green building evaluation standards. Chapter 5 (Resource Conservation) of "Assessment Standard for Green Building" GB/T 50378-2019 sets clear requirements for water supply and drainage systems: the water efficiency grade of water-saving fixtures should reach Grade 2 or above; a reasonable water quality monitoring system should be provided; rainwater harvesting and reuse or reclaimed water reuse systems should be adopted; and the vertical zoning of water supply systems should be reasonable. At the same time, "Standard for Water Saving Design in Civil Building" GB 50555-2010 sets specific requirements for water-saving design, including determination of water-saving quotas, selection of water-saving sanitary fixtures, and measures against overpressure outflow in water supply systems. Hotel design should fully adopt water-saving sanitary fixtures: toilet water consumption should not exceed 5 L/flush, faucet flow rate should not exceed 0.15 L/s, and shower flow rate should not exceed 0.12 L/s. A comprehensive water metering system should be provided to achieve metering by unit and by functional area.
List of Commonly Used Standards for Water Supply and Drainage Design and Update Trends
The list of national and industry standards involved in hotel water supply and drainage design is as follows: GB 50015-2019 "Standard for Design of Building Water Supply and Drainage", GB 50974-2014 "Technical Code for Fire Water Supply and Hydrant Systems", GB 50084-2017 "Code for Design of Sprinkler Systems", GB 50242-2002 "Code for Acceptance of Construction Quality of Building Water Supply, Drainage and Heating Works", GB 50555-2010 "Standard for Water Saving Design in Civil Building", GB/T 50378-2019 "Assessment Standard for Green Building", GB 55015-2021 "General Code for Energy Efficiency and Renewable Energy Utilization in Buildings", GB 50140-2005 "Code for Design of Extinguisher Distribution in Buildings", and CJJ 142-2014 "Technical Specification for Rainwater Drainage System on Building Roof". Designers are advised to follow the standard revision trends of the Ministry of Housing and Urban-Rural Development and update their knowledge base in a timely manner. Since 2023, a number of full-text mandatory engineering construction codes (GB 550xx series) have been implemented successively and are used in coordination with current recommended standards.