Medical gas system is one of the most common and indispensable special systems in hospital buildings. The system is mainly for patient treatment, diagnosis, prevention, or to provide driving for surgical instruments and tools. Because the system is composed of various air source systems, monitoring and alarm systems, valves, terminal components, pipeline distribution systems, etc., its process and pipeline are complex and special, and in the design or construction and installation process, it is closely related to the building structure, purification system, power distribution system, medical technology and other professionals. Coupled with the imperfection of relevant national standards and the uneven comprehensive capacity of relevant domestic design or construction units, there are also many quality problems in the design or construction installation process, especially some common problems, so this paper summarizes and discusses the common problems on this basis.
1. Qualification requirements for design or construction organization
Since the pipelines in the medical gas system are pressure pipelines, and the gas pressure value is below 1.0MPa, according to the requirements of the “Special Equipment Safety Supervision Regulations”, the maximum working pressure of the pressure pipelines within the supervision and management scope is greater than 0.1MPa gas, flammable liquid, and the nominal diameter Pipes larger than 25mm; therefore, according to this regulation, the design and installation of pressure pipes must be entrusted with the corresponding level of design or installation qualification conditions. If the above pressure value requirements are applied, the pressure pipe design or installation permit level should reach GC level and above.
In addition to the pressure pipes of the system, there are more unit equipment, monitoring and alarm systems, and electrical pipelines. If required by the implementation measures of the construction industry, the construction unit should also have relevant construction qualifications such as mechanical and electrical equipment installation.
2. Common problems in the process of the special scheme or drawing design
The medical gas system itself is very complex and special, and the system cannot be carried out according to the traditional design mode in the scheme or drawing design process, which has caused many hospital projects to generally encounter difficulties in the system design. Similarly, in the process of special scheme or drawing design, the main manifestations are that the design depth, equipment room setting and supporting system, and system technology itself are more prominent. The specific content is as follows:
2.1 The content is incomplete or the depth does not meet the bidding or construction requirements.
2.1.1 Insufficient design depth, lack of general design description, main material and equipment list, floor plan, system diagram, large-scale diagram of machine room, node section diagram, large-scale diagram of equipment belt, outdoor general diagram, etc.
2.1.2 The general description of medical gas design is not detailed enough, such as pipeline material, unit interchange, control method, tightness, purging, grounding, etc.
2.1.3 Drawings such as liquid oxygen tank station, air, vacuum, manifold and other system schematic diagrams, elevations and equipment configuration instructions are missing or not detailed.
2.1.4 There is a lack of equipment with a large sample map, and the detailed layout of gas terminals, lighting, switches, sockets and other equipment cannot be identified.
2.1.5 The design depth of the oxygen, air, vacuum and other equipment rooms is not enough, such as the decompression device of the oxygen system, the filter settings and parameters of the vacuum system are not detailed, the power distribution power in the equipment room is not clear, and the unit equipment foundation is not clear, etc.
2.2 The setting of the computer room and supporting systems are not well considered
2.2.1 Design conditions were not put forward for the location of the computer room and power distribution of each system, resulting in the addition of computer rooms and power distribution facilities during the construction process.
2.2.2 The fire distance between the oxygen storage tank (liquid oxygen station) greater than 5m³ and buildings and structures is less than 25m, which cannot meet the fire acceptance requirements.
2.2.3 The medical oxygen bus bar is located in an underground or semi-underground building, which cannot meet the requirements for fire acceptance.
2.2.4 The computer rooms of air, vacuum, oxygen bus and other systems are arranged in the same room, and the walls are not divided according to the specification requirements.
2.2.5 Air, vacuum, oxygen bus and other system rooms are not equipped with ventilation, exhaust, ventilation, cooling and noise reduction measures as required.
2.3 Insufficient design of system technology
2.3.1 Medical oxygen, medical vacuum, and air pipelines in life support areas such as the operation department, first aid, and ICU do not supply air from the air source in one way, or do not provide two-way air supply, so the air supply requirements in this area cannot be guaranteed.
2.3.2 The cold dryers of the air system should be set in parallel instead of in series under normal use;
2.3.3 The drainage treatment and discharge problems, exhaust sterilization and other issues generated by the liquid ring vacuum pump of the vacuum system are not clear, and the bidding and construction requirements cannot be met;
2.3.4 The number of sockets on equipment belts in VIP or critical care and first aid areas is insufficient or multi-functional sockets are not selected, resulting in later design adjustments;
2.3.5 The medical gas pipelines in most hospital buildings are not laid in special tube wells;
2.3.6 The medical gas pipeline is set in the ventilation and exhaust shaft or co-located with the drainage pipe well, which does not meet the specification requirements;
2.3.7 In addition to the local alarm installed on the medical gas source, each monitoring point is not equipped with an independent alarm display device as required;
2.3.8 The medical gas decompression device is not equipped with a double-circuit type including a safety valve, and the safety and reliability are poor;
2.3.9 In the medical gas system drawings designed after August 1, 2012, the vacuum and compressed air supply sources are not equipped with emergency backup power; the gas source alarm and the area alarm power supply are not connected to the emergency backup power of the hospital at the same time. The sensor is powered independently, power supply is not connected to the hospital’s emergency backup power supply and other problems are still common.
3. Common problems in the process of on-site construction and installation
In the process of medical gas construction and installation, rework or rectification during the construction process is often caused by insufficient depth of design drawings, unreasonable system process design, and failure of the construction unit to construct according to the drawings, etc. The common problems caused by the above reasons are mainly reflected in the process Installation, pipeline connection, system grounding, commissioning, etc., the details are as follows.
3.1 Oxygen manifold, compressor air room, vacuum machine room, etc. are not constructed according to the design, placed in the same room or not separated by a partition wall, and the wall material and door material cannot meet the fire acceptance requirements.
3.2 The air storage tank and supporting pipelines of the air compression system are incorrectly connected, mainly reflected in the leakage of bypass pipes and valves or irregular valve settings.
3.3 The construction process of the cold dryer pipeline and the third-stage filter of the air compression system is wrong, mainly because the third-stage filter is installed in the wrong order. There are four types of filters, G, H, D, and A, and G is the supervisor Road filter, H—high-efficiency oil removal filter, D—dust removal filter, A—ultra-high efficiency filter, the specific installation sequence should be strictly in accordance with the design, specification requirements or manufacturer’s instruction manual.
3.4 The connection process of the vacuum tank pipeline in the vacuum machine room is wrong, mainly reflected in the vacuum tank inlet and outlet pipelines, such as wrong connection at low inlet and high outlet.
3.5 The sewage discharge pipe and exhaust pipe of the gas-water separator (drainage tank) in the vacuum machine room are not constructed according to the design or specifications, and the exhaust pipe is not connected to outdoor discharge.
3.6 The connection between the vacuum pump and the intake pipe and exhaust pipe is not flexible as required.
3.7 The installation slope of the medical vacuum pipeline is less than 0.002.
3.8 The grounding of medical gas pipelines is not constructed in accordance with the regulations that “the grounding distance should not exceed 80m, and should not be less than one place”.
3.9 Due to the lack of consideration in the layout of the equipment, the maintenance access around the on-site unit is less than 1m, which will affect the later maintenance and repair work.
3.10 The connection of the carburetor pipeline in the outdoor oxygen station is wrong, mainly reflected in the leakage of the bypass pipe and valve or the valve setting is not standardized.
3.11 The liquid filling port of the liquid oxygen tank is not equipped with anti-misconnection and protection facilities, and the installation direction of the liquid filling port is not convenient for tank truck connection.
3.12 For the machine room equipped with water ring vacuum pump, relevant drainage facilities, such as ground drainage ditch, etc., should be made according to the specifications.
3.13 Carry out equipment and pipeline purging, leakage, pressure test and other tests and commissioning work according to the requirements of the current national standards and design documents, and provide complete relevant records and reports signed by the supervisor. This work is often not given enough attention , or there are situations such as coping.
3.14 After the on-site test and trial run, the construction unit provides the owner with a detailed self-inspection report, and the results must meet the acceptance criteria, but this work is often ignored.