Planning Space for Pipe Organs: Components
Details of pipe organ construction are best learned from a pipe organ builder; however, the following general information is offered as a primer.
The three basic elements of a pipe organ were mentioned on page 2 and are covered in more detail below. Another important element is the method of connection between console and pipes/windchests. This is called the action. The type of action employed determines to a great extent the layout of the organ components. (See below) There are two types of action in general use today.
Mechanical action
Mechanical action organs, or tracker organs as they are commonly called, are usually built within a wooden cabinet called an organ case which is located within the room. Tracker organs have many direct mechanical connections between the console and the pipes/windchests. The console is usually built into the lower front of the organ case and is called the keydesk.
Mechanical action organs sometimes employ a separate or detached console. When this configuration is used, the mechanical connections between the console and the organ case are installed in a chase which is on or built into the floor. A chase size of 16" high by 60" wide is adequate for most installations. The organ builder will provide more specific requirements.
Electric Action
Electric action organs are built either within an organ case or located within organ chambers or other space provided within the room. The action between the keyboards and the windchests is electrical, operating on 10 to 30 volts direct current. Therefore a detached console is often used. The linkage between the console and the pipes is a flexible electrical cable, so the console can be placed in the most convenient location to suit the needs of the church. However, care should be taken to avoid excessive distance. The console may also be mounted on a movable platform, or casters.
The Pipes/Windchests
You can see the arrangement of pipes/windchests in a mechanical action organ and an electric action organ on pages 9 and 10. The configuration and arrangement may vary from builder to builder but the space necessary for the instrument is somewhat universal.
The space required for a mechanical action organ is defined by the size of the case. The weight is borne on the footprint area of the case and floor loads can vary from 50 lbs/sq.ft. to as much as 1,000 lbs/sq.ft. for a large instrument with a small footprint.
The windchests are the largest and heaviest component to be considered in the layout of an electric action organ. (See page 11.) They are approximately 8' to 10' in length and vary in width depending on the number of ranks. The floor in the area where these parts are located should be capable of supporting 450 to 500 lbs per rank. This generally means floor loads of 50 to 100 lbs/sq.ft. However, weight can be concentrated or distributed and can affect the support needed. The organ builder should be consulted for specific information.
It is important to consider that access to these components is required for regular tuning and service. The chart on page 15 gives some handy references to size and weight of pipes/windchests.
A Ten Rank Electric Action Windchest
The Console
| Average Console Size and Weights | ||||
|---|---|---|---|---|
| Manuals | Width | Depth | Height | Weight |
| 2 (small) | 5' | 5' | 3'9" | 500 lbs. |
| 2 (large) | 6' | 5' | 4'2" | 700 lbs. |
| 3 | 6'7" | 5'6" | 4'4" (or more) | 1,000 lbs. |
| 4 | 6'10" | 6' | 4'8" (or more) | 1,300 lbs. |
The Blower
All pipe organs must have a system to deliver wind (pressurized air) to the windchests. The air is pressurized by a motor-driven centrifugal blower. It is ideally located in an acoustically isolated area in order to prevent mechanical noise from being transmitted into the room where the organ is to be heard. The air should be filtered and drawn from the room where the pipes/windchests are located. A wind trunk or wind line must be supplied from the blower to the organ and this is normally the responsibility of the purchaser.
The wind lines required range from 6" to 15" in diameter with 8" to 12" being typical. It is essential that all seams in the wind lines be air-tight and should be formed with lapping in the same direction as the wind's travel. Taped joints are not sufficient. Whatever their material, wind lines should be capped at both ends during the building construction process to keep the lines free from dust and debris. Lines running through unheated/uncooled space should be insulated. Lines should be terminated 6" to 12" inside the blower room and the organ area. Wind lines may be either 24 gauge galvanized or PVC pipe if local building codes permit.
