the BHCA is the number of calls made during the busiest hour during the day. to calculate find the number of calls made during one hour intervals during the day.
e.g 6.00 to 7.00, 7.00 to 8.00, 8.00 to 9.00 or 7.30 to 8.30, 8.30 to 9.30. this should be taken for a number of days. the call attampt for the one hour period with the highest number of calls made is the BHCA