When can equipment like blowers and fans be installed without protective measures?

The correct choice indicates that equipment such as blowers and fans can be installed without protective measures in specific scenarios, specifically when these components are intended for installation inside ducts and when they are engine-driven according to the applicable ABYC standards, such as P-4.

When blowers and fans are used within ducts, they are generally not exposed to external elements, minimizing the risks that protective measures typically address. The air and airflow are contained, which reduces the likelihood of accidental contact or debris entering the machinery. This containment makes additional protective measures unnecessary, as the intended use is inherently safer within a ducted system.

For engine-driven equipment as specified in ABYC P-4, compliance with industry standards ensures that safety precautions and engineering designs are taken into account. If the equipment meets certain safety criteria and standards outlined by ABYC, it can be considered suitable for installation without additional protective measures.

In summary, both of these scenarios demonstrate environments where adequate safety is naturally ensured either by design or due to the operational context of the equipment, allowing for the installation of blowers and fans without further protective requirements.