Lerch Bates Inc. Building Insight

Global Leaders in Technical Consulting for the Building Industry

To boson or not to boson?

When is it acceptable to use a bosons’ chair?

A bosons’ chair is a controlled descent device used by window washers across North America. A bosons’ chair provides the window washer with an efficient means of accessing the exterior building windows or interior building windows in the case of an atrium.  First of all let’s define what a bosons’ chair should be used for, that is, exclusively window cleaning. A bosons’ chair should not be used for building maintenance, tasks such as; caulking, glass replacement, metal refinishing, re-glazing etc… The building design should also include provisions for these types of operations as well.

While it is not our preferred method for exterior building maintenance, often times the building owner will opt to include only the necessary tiebacks that are required to support a bosons’ chair system.  In this instance, the design should be compliant with the “International Window Cleaners Association (IWCA) I-14 ANSI Standard for Window Cleaning Safety” along with OSHA 1910.66 standards and ASME A120.1 requirements. (Keep in mind, that the IWCA I-14 will only allow the use of bosons’ chairs where the building height does not exceed 390’)

Let’s go back to the issue at hand; while we have established that a bosons’ chair is acceptable for window cleaning, if the building design includes only these provisions, how will commonplace exterior building maintenance operations such as, glass replacement, re-glazing and metal refinishing be performed?

A common misconception is that temporary riggings or aerial work platforms (cherry picker) will be necessary.  These solutions are not the answer. Aerial work platforms can be expensive to rent and access to the base of the building may not be available or the unit may not be available in your area. Temporary rigging can be obtrusive to the building users and can often times be unsafe.

It is our recommendation that at a minimum, a davit and socket system be provided. This solution will allow for the use of a bosons’ chair while at the same time provide a safe and effective means for performing exterior building maintenance functions. Your building is long term asset, why cut corners when it comes to exterior building maintenance?   The first thing a potential tenant or purchaser sees is the building exterior; it is the face of your building it should be easily and safely maintained.

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