Which of the following is a key element of the pre-abatement sequence?

The pre-abatement sequence is crucial in safely handling asbestos removal and involves several important steps to ensure a controlled and safe environment prior to commencing any abatement work. The construction of barriers is a key element because it establishes containment areas that prevent the spread of asbestos fibers to surrounding spaces. This containment is vital for worker safety, as well as the protection of building occupants and the general public.

Barriers create controlled zones that limit exposure to asbestos by isolating the work area. This is typically achieved through physical barriers, such as sheeting and negative air pressure systems, which together help to contain the hazardous materials and prevent contamination of clean areas. Establishing these barriers is an essential first step in the process, ensuring that all subsequent abatement activities can be conducted with minimized risk of fiber release.

The other options represent important aspects of asbestos management but occur either during the abatement process or afterward. For instance, final cleanup and testing air quality are crucial post-abatement steps that verify whether the area is safe for re-entry. Reinforcing positive pressure may be used during abatement to protect against contamination but is not an initial step in the sequence. Therefore, the construction of barriers is central to the pre-abatement sequence.