Safety, Code Compliance, and Plan Reading
The Focus Four and the numbers
OSHA 29 CFR 1926 governs construction. The Focus Four are falls, struck-by, caught-in/between, and electrocution. Fall protection is required at 6 ft in construction; guardrails are 42 in plus or minus 3 in, with a midrail near 21 in and 3.5 in toe boards. Ladders: 4:1 angle, extending 3 ft above the landing, three-point contact. Scaffolds: fall protection at 10 ft, base width adequate for height, fully planked, and designed for 3-4 times the intended load. Report fatalities to OSHA within 8 hours and in-patient hospitalizations, amputations, or eye loss within 24 hours; maintain the OSHA 300 log.
Code compliance
IBC occupancy groups: A assembly, B business, E educational, F factory, H hazardous, I institutional, M mercantile, R residential, S storage, U utility. Construction Types I through V run from most to least fire-resistive. Allowable height and area come from combining occupancy and construction type. Means of egress: two exits generally required above 49 occupants, travel distance limits by occupancy, egress width per occupant, and panic hardware thresholds. The certificate of occupancy is issued by the building official after final inspections - not by the architect.
Plan reading
Orientation: title block, north arrow, grid lines, and scale. A scale of 1/4 in = 1 ft 0 in means every quarter inch on paper is one foot in the field. Read section and detail callouts, door and window schedules, and general notes; specifications are organized by MasterFormat division (03 concrete, 05 metals, 07 thermal and moisture, 08 openings, 09 finishes).
Worked example
On a 1/4 in = 1 ft 0 in plan, a wall measures 3-1/2 in on the print: 3.5 x 4 = 14 ft 0 in actual. If the measured value were 3/8 in, that would be 1.5 ft, not 3.5 ft - scale errors are a classic distractor.