Draft is measured by receiving pressure across which of the following options?

Draft is a critical concept in heating, ventilating, and air conditioning (HVAC) systems, primarily related to the movement of air or flue gases through a chimney or duct system. Measuring draft typically involves assessing the pressure difference across a specific area in the system, which can be accomplished using various devices.

Venturi meters, orifice plates, and flow nozzles all operate on the principle of measuring pressure differences. Each of these devices can create a drop in pressure that correlates to fluid dynamics principles, specifically Bernoulli's principle. By measuring the pressure before and after the flow restriction, one can determine the draft created in a system.

Given that all these devices can effectively be used to measure draft by capturing the pressure differential, the correct answer encompasses all three options. This understanding highlights the versatility of these devices in practical applications related to airflow and pressure measurements, showcasing why any of them can be a valid answer for measuring draft.