This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol2", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
These are generally selected from a trade list. If in a range, the cast-iron underframes will also most probably be supplied with them. The top may or may not be included. If it is not included, number it and describe, stating size and method of fixing. Include the rounded edge, quadrant corners, etc., and the perforations, stating how many. Take the plinth per foot run. State size and how fixed, and number the mitres, returned ends, etc.
Wire Balloon Covers to top of ventilating pipes. Number.
As before described.