There should be at least seven points on the scale ending with "very acceptable" and "very unacceptable." The standard also specifies that when asking thermal sensation questions, the scale should be "cold, cool, slightly cool, neutral, slightly warm, warm, and hot." For mechanically conditioned spaces, the PMV-based comfort zone has to be determined, which includes measuring and recording the metabolic activity and clothing insulation. The comfort zone boundaries must be adjusted to the air movements, and the zone conditions should be adjusted to avoid local thermal discomfort. For occupant-controlled naturally conditioned space, the adaptive model shall be used to determine the thermal comfort boundaries. For such spaces, the indoor and outdoor air temperature and mean radiant temperature and the air speed need to be measured. "ANSI/ASHRAE Standard 55" provides guideline on the position, time, and equipment accuracy of the physical measurement. The measurement locations should be where the occupants are expected to spend time in. If there are multiple such locations, the measurement can be performed at a representative location. In cases that the optimal representative location cannot be found, the standard suggests specific locations in the space. For seating occupants, the air temperature and air speed measurements shall be taken at heights of 0.1, 0.6, and 1.1 m (4, 24, and 43 in.), and operative temperature and PMV shall be measured at 0.6 m (24 in.). The heights need to be adjusted for standing persons. Local discomfort caused by radiant temperature asymmetry shall be measured at occupants’ locations, with the sensors oriented to catch the maximum surface temperature differences. The standard suggests that the time of measurements should last two or more hours long, and it should also be a representative time of the year for this specific building. Measuring time step should be no more than five minutes for air temperature, mean radiant temperature, and humidity, and no more than three minutes for the air speed. In order to achieve acceptable results, the standard also suggests the minimum equipment accuracy based the current industry standard. When extracting environmental data from the Building Administration System, one should evaluate the location, height, and time step of the sensors based on the previous suggestion. To evaluate the probability of satisfaction from satisfaction surveys, the standard suggests dividing the number of the votes falling between "just satisfied" and "very satisfied" by the total number of votes in that questions. The answers of open-ended questions from "very dissatisfied" occupants should be documented for later analysis. For point-in-time surveys, the comfort evaluation shall be performed by dividing the number of votes between -1 and +3 by the total number of votes.