6.2.1 Operating Light

To minimize the impact of obstructions on the clean airflow, the operating light or LED Surgical Light is required to have a streamlined housing; therefore, multi-head type operating lights are commonly used, as shown in Figures 6.2 and 6.3.

Figure 6.2 One type of operating light

Figure 6.3 One type of frame-type operating light

【Reference】 In a modern operating room, the air supply plenum (commonly known as the supply air ceiling) is arranged directly above the operating table, and the operating light is also positioned at the very center of the supply air plenum. In this way, the shape of the operating light often obstructs the supply airflow and generates vortices. When a conventional dish-type operating light is placed in a vertical airflow, its main vortex region occurs in the upper part of the operating table. Tests show that the length of the vortex is approximately 5 times the width of this obstruction (installation gap); therefore, for relatively large obstructions such as operating lights When the object is within the supply airflow, a set of measured values provided by Japan's Yamada Company can be used for reference (Figure 6.4); when the diameter of a lamp with a streamlined shade is 20 cm, the vortex it generates disappears at approximately twice the diameter below the lamp.

(a) Return-flow contamination when the pollution source is 0.8 m from the surgical light　　(b) Return-flow stagnation contamination when the pollution source is 1.4 m from the surgical light

(c) Return-flow contamination when the pollution source is 0.8 m from the frame-type surgical light

Figure 6.4　Contamination beneath a disc-type shadowless light

6.2.2 Installation of Shadowless Lights

When a shadowless light is installed, it must pass through the supply air plenum; therefore, a sealed enclosure should be provided around the adapter frame at the penetration point, and then the structural treatment at the installation location should be carried out according to the installation requirements in the shadowless light catalog, as shown in Figure 6.5. The height of the adapter frame is the height difference between the installation height of the shadowless light and the floor slab.

Figure 6.5　An example of the base of a shadowless light

6.2.3 Design of the Shadowless Light Base

The static load-bearing capacity of the shadowless light base is generally required to be above 300 kg (the dynamic load can generally reach 2 000 kg or more), with a power consumption of approximately 0.5 kW; each manufacturer's catalog contains specific requirements, and the design must be carried out accordingly, with confirmation that the structure is firm, as shown in Figure 6.6. Figure 6.6　An example of the installation drawing of the shadowless lamp base (bracket) structure

6.2.4　Installation Requirements for Shadowless Lamps Passing Through the Leakage-Preventing Supply Air Ceiling

First fix the shadowless lamp mounting base to the building ceiling slab, install the shadowless lamp pole, adjust it to level, install the leakage-preventing supply air ceiling, and finally install the lamp; see Figure 6.7.

Figure 6.7　An example of the schematic diagram of a shadowless lamp installed through the leakage-preventing supply air ceiling