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Is the mezzanine under the elevated floor considered a confined space
2025/7/16
The space is arranged with the support structure of the raised floor, process equipment pipelines, electrical pipelines, etc. As a spatial component within a cleanroom, in system operation and maintenance, it is often necessary to enter the mezzanine under the raised floor to carry out maintenance and installation work. There are often different voices in the industry regarding whether the mezzanine under elevated floors is a confined space. This article provides a brief introduction to this issue.
The definition of confined space is described online as follows: It refers to a space that is enclosed or partially enclosed, not designed as a fixed workplace, where personnel can enter for work, and is prone to the accumulation of toxic, harmful, flammable and explosive substances or insufficient oxygen content.
To be defined as a finite space, the following four conditions must be met simultaneously, and none of them can be missing:
1. Not designed as a fixed workplace;
2. Limited or restricted imports and exports;
3. It is prone to cause the accumulation of toxic, harmful, flammable and explosive substances or insufficient oxygen content;
4. There is a possibility and demand for personnel to enter.
It can be clearly seen just from the four conditions that the definition needs to meet.
1. Not designed as a fixed workplace;
The mezzanine under the elevated floor is of course arranged for temporary maintenance and installation work, and it is certainly not a fixed "workplace". This point is in line with the statement "not designed as a fixed workplace".
2. Limited or restricted imports and exports;
Entering the mezzanine under the elevated floor for work is basically done through the return air wall or by lifting the fixing screws of the elevated floor. Of course, the entrances and exits are also "limited or restricted", which conforms to the principle of "limited or restricted entrances and exits".
3. It is prone to cause the accumulation of toxic, harmful, flammable and explosive substances or insufficient oxygen content;
The article also introduced at the beginning: The mezzanine under the raised floor is a "crucial spatial area for the circulation and purification of clean air in a cleanroom". The air flowing in this space comes from the cleanroom space and is delivered to the mezzanine under the raised floor through the perforated plates of the raised floor. Then, it enters the upper static pressure box of the cleanroom through the return air duct and coil, and is finally conveyed into the cleanroom by the FFU. In this way, purification and temperature and humidity regulation are continuously completed. To meet the needs of the production environment. Therefore, there will be no accumulation of toxic, harmful, flammable or explosive substances or insufficient oxygen content in the interlayer under the raised floor. This point does not conform to the statement that "it is prone to cause the accumulation of toxic, harmful, flammable and explosive substances or insufficient oxygen content."
4. There is a possibility and demand for personnel to enter.
The lower mezzanine of the raised floor is arranged with process equipment pipelines and electrical pipelines. In actual production and operation and maintenance, it is often the case that secondary pipeline laying is required for machine setup and daily maintenance needs to be carried out in the lower mezzanine to complete the work content of this part. Therefore, the possibility and demand for personnel entry arise. This point is in line with the possibility and demand for personnel to enter.
For the four conditions defined as limited space, since the mezzanine under the raised floor does not meet the requirements of "easily causing the accumulation of toxic, harmful, flammable and explosive substances or insufficient oxygen content", the mezzanine under the raised floor cannot be defined as an effective space.
As the mezzanine under the raised floor is located in a clean room and meets three of the conditions for defined effective space, many enterprises manage the operations in this space area as a confined space area. In fact, it's not surprising.
The purpose of implementing approval and control for confined space operations is to prevent errors and omissions through comprehensive review and inspection, ensure the improvement of work quality and prevent accidents. Therefore, when working in the mezzanine under the elevated floor, it is still necessary to strictly follow the rules and regulations as well as the standard procedure sequence. The approval of the work ticket, the thorough preparation of the work, the confirmation of the work environment, on-site protection and dedicated supervision are all indispensable.
Attached: definition of a fixed workplace
Youdaoplaceholder0 A fixed workplace refers to a relatively stable physical space that is used for work purposes for a long time. It has the following main characteristics:
1. Youdaoplaceholder0 Location certainty : Fixed workplaces have clear geographical locations, such as offices, workshops, etc. The locations of these places will not change easily, and employees can go to work based on fixed addresses.
2. The relative fixality of facilities : It is equipped with basic facilities related to work and they are relatively fixed, such as desks and chairs, computers, filing cabinets in the office, machinery and equipment, production lines in the factory workshop, etc. These facilities generally do not change frequently.
3. Relative stability during working hours : During normal working hours, this place is mainly used for work-related activities, and employees complete their work tasks here.
4. Youdaoplaceholder0 differs from temporary workplaces : Unlike temporary or occasionally used workplaces, a fixed workplace is a long-term and stable location for work .
