This subdivision is primarily base pipe and related materials. the pip may be used by any of the mechanical disciplines i.e. plumbing, fire protection, heating and air conditioning.

Non-specialty estimators who are unfamiliar with the details of plumbing systems may choose to take off fixtures only, and use general percentage markups for the various elements of the plumbing system.

Most pipe is priced first as straight pipe with a joint (coupling, weld, etc.) every 10 feet and a hanger usually every 10 feet. There are exceptions with hanger spacing such as for cast iron pipe (5 feet), and plastic pipe (3 per 10 feet).

Fittings - When preparing an estimate, it may be necessary approximate the fittings. Fittings usually run between 25% and 50% of the cost of the pipe. The lower percentage is for simple runs, and the higher number is for complex areas, such as mechanical rooms.

Historic Restoration Projects - For historical restoration projects, the systems must be as invisible as possible, and pathways must be sought for pipes, conduit, and ductwork. While installations in accessible spaces (such as basements and attics) are relatively straightforward to estimate, labor costs may be more difficult to determine when delivery systems must be concealed.

General Estimating Tips for Plumbing

Review all construction documentation before proceeding with the estimate for Plumbing. It is not unusual to find items on the plans, but not in the specifications; or they may be in the specifications but not on the drawings. Also check any and all communications; the owner may have requested a change or expressed a concern or a specific need, and not have had it included in your drawings or specifications.

Review All Drawing Divisions - It is important to review all of the drawings available to ensure that the systems called for will physically fit where they are supposed to. Sometimes the architect subcontracts out the structural design, so if the drawings are not carefully coordinated, a conflict may result.

Check Drawing Scales - When utilizing drawings from different sections of the plans, always check to see if the drawing scales are the same. It has happened that an estimator has ended up with twice the length of piping needed (or worse, half) because he/she was not aware that the drawing scales varied from structural to mechanical.

Document All Inconsistencies - All inconsistencies with standard practice, conflicts, omissions, and other concerns should be addressed before the final estimate is resolved. Do not rely on memory, which can become quickly overloaded in a rush situation.

Read more estimating tips for plumbing.