152 B. Pridham et al. conducted during this phase that included reviews of baseline test data collected early in the project, as well as structural modelling to identify areas of concern. As the facility entered the construction phase, planning for the level one space evolved to include an ambulatory surgery clinic featuring patient bed space and operating rooms. A second phase of detailed design followed to address fit-out of the space. This included vibration measurements on the constructed building and detailed numerical modelling for solution development. 19.4.2 Design Criteria Specification of appropriate vibration criteria for the surgical clinic required consideration of the following vibration disturbances: • tactile motion of the level one floor that could result in discomfort of occupants; • motions at the supports of medical equipment that could degrade functionality and interrupt surgical procedures; and, • motions of the superstructure that could result in audible noise or perceptible vibration from equipment such as lighting or screens and monitors. Criteria relating to items #1 and #2 are specified based on published guidance by the Facilities Guidelines Institute [10], criteria related to research facilities that have evolved over the past ten years [11, 12], and experience with design of similar facilities. Due to the complex nature of vibration-induced (structure-borne) noise there are no commonly applied vibration criteria to limit noise disturbances caused by structural motions. Recommendations were developed based on thresholds related to ground-borne noise disturbances in acoustically sensitive areas (i.e., ground motions causing noise emissions from building elements). See for example [13]. Table 19.1 is a summary of the vibration criteria applied to the design. As is customary for the design of research and healthcare facilities, the criteria are specified as root-mean-square vibration velocities in one-third octave bands between 1 and 80Hz. Separate criteria are proposed for the ground floor slab on level one and for the overhead ceiling structure supporting equipment and building services (ductwork, lighting, plumbing etc.). The design criteria for the ground on level one relates to comfort of patients and staff, whereas criteria for the superstructure relate to vibration-sensitive ceiling-mounted devices and generation of noise. The criteria are applicable to any plane of motion. Some additional notes to Table 19.1 are as follows: • the 2000 micro-in./s lower bound criterion for Patient Care is associated with a background noise level of 25 dBA and the 6000 micro-in./s upper bound is based on a 45 dBA background noise level. The FGI recommends a 45 dBA background noise threshold for patient rooms. As such, the lower bound would be appropriate if actual sound levels in these spaces were closer to 25 dBA. • the 4000 micro-in./s criterion recommended for the ground in level one ORs is based on general surgical use. Specialized surgical procedures featuring floor-mounted microscopes and lasers require a lower threshold. • The 1000 micro-in./s threshold recommended for the overhead structure in ORs and Procedure Rooms addresses mounting of surgical microscopes to the ceiling structure. This criterion was proposed in [14] and has been shown to be appropriate in field tests [15]. In the early stages of the project, when the space was planned to be shelled, the criteria for ORs and Procedure Rooms were applied to the results of a screening-level review. Table 19.1 Summary of vibration criteria applied during detailed design Space Level 1 ground Superstructure/Ceiling support Patient care area 6000 micro-in./s (ISO-residential night) 2000–6000 micro-in./s (Class A—ISO residential night) ORs and procedure rooms 4000 micro-in./s (ISO-operating theatre) 1000 micro-in./s (Class B)
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