Diaphragm Valve or Diaphragm Actuator Diaphragm Valve or Diaphragm Actuator DamienLong (Mechanical) (OP) 11 Mar 16 01:20 Does the diaphragm valve symbol in ISA represent the actuator or the type of sealing. Does anyone have a link that can clarify this? Thanks, Damien RE: Diaphragm Valve or Diaphragm Actuator xnuke (Electrical) 11 Mar 16 06:26 In ANSI/ISA 5.1-2009, the diaphragm valve symbol in "Table 5.4.1 — Final control element symbols" shows the type of sealing. The diaphragm actuator symbol is shown in "Table 5.4.2 — Final control element actuator symbols." xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.