User's Manual

Design
P/N 81-CO2MAN-001 3-69 September 2013
•CO
2
systems with no more than two cylinders may employ a single pilot cylinder.
•CO
2
systems with three or more cylinders shall employ one more pilot cylinder than the
minimum required for actuation of the entire cylinder bank.
For systems with three or more cylinders, it is recommended to employ an additional pilot
cylinder per every ten cylinders, provided the manifold uses stepped pipe sizes (see
Paragraph 3-12.4.2.2). The pilot cylinder quantity shall be proven acceptable by the discharge
test described in Paragraph 4-7.7. During this test, one pilot cylinder shall be operated as a
slave cylinder.
It is generally practiced to locate the pilot cylinder(s) together, starting at the second cylinder.
See Figure 3-11 for an example.
Figure 3-11. Pilot Cylinder Position within Manifold
3-13.3 Actuation Classifications
Three actuation classifications apply to CO
2
systems: automatic, normal manual, and
emergency manual.
3-13.3.1 AUTOMATIC
Automatic actuation is a system operation that does not require any human action. Automatic
detection and actuation shall be used, except where manual only actuation is acceptable to the
authority having jurisdiction and where automatic actuation could result in an increased risk.
Automatic detection shall be by any listed or approved method or device that is capable of
detecting and indicating heat, flame, smoke, combustible vapors, or an abnormal condition in
the hazard such as a process trouble that is likely to produce fire.
3-13.3.2 NORMAL MANUAL
Normal manual actuation is a system operation that requires human action. The actuating
device shall be easily accessible to the hazard at all times and shall be clearly recognizable for
the purpose intended. Operation of the device shall cause complete operation of the system
and shall not cause the time delay to recycle. Normal manual actuation may incorporate
electrical, mechanical, pneumatic, or other devices.
1
2
3
4
5
6
7
8
9
PILOT
CYLINDERS