Vibration Design Practices Towards More Sustainable Lab Floors

Omer Tigli, McNamara Salvia Structural Engineers

It has been a general practice to design lab floors for a vibration criterion of 2,000 micro-inches/second (mips) in North America. This practice may have roots to the generic vibration criterion (VC) curves developed by Gordon C.G. in early 1990s, where the vibration limit of 2,000 mips (VC-A) is recommended for optical microscopes up to 400X, microbalances, etc. Although humans cannot feel such low vibration levels, 8,000 mips sets the limit for barely perceptible floors, while 16,000 mips sets the limit for human comfort in office/lab settings.

Since a typical lab fit-out includes both lab and office spaces, a lab floor designed to 2,000 mips carries an unnecessarily high carbon footprint at the office spaces. Even at the lab spaces, low-vibration levels may only be needed for specific equipment located on limited regions of the lab floor, further reducing the sensitive areas that would actually need the 2,000 mips limit. Moreover, some lab tenants may prefer to sit their equipment on high-performance isolation tables, which may eliminate the need of a 2,000 mips floor.

The session will present case studies of lab floor designs and identify structural design strategies that can reduce the carbon footprint of new lab floors. These include designing the base structure to a vibration limit of 8,000 mips with post-construction upgrades on select bays per specific user demands and investigating more sustainable floor constructions such as mass timber.

Learning Objectives

• Identify three essential components of any vibration concern--source, path, and receiver;
• Learn how footfall excitation drives the structural design of laboratory floors and its share on the carbon footprint;
• Learn about structural and non-structural vibration mitigation options; and
• Learn about design strategies and optimization tools that lead to more sustainable lab floor designs.

Biography:

Omer Tigli Ph.D., P.E., is vibrations group director at McNamara Salvia Structural Engineers in Boston, MA. With over 22 years of research and consulting experience on structural vibrations and a unique set of skills as a researcher, a vibration consultant, and a structural engineer, Omer delivers creative, employable, and cost-effective solutions.

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