{"schemaVersion":1,"slug":"ansi-gas-flow-switch","name":"ANSI/IEEE Gas flow switch form","kind":"symbol","abbreviation":"FS GAS","aliases":["HFS11S20","VFS11S20","IEEE Flow Switch Normally Open - Gas","ANSI Gas flow switch"],"category":"control-circuits","drawingTypes":["Schematic"],"referenceFamilies":["IEEE / ANSI","Manufacturer"],"summary":"IEEE-library form of gas flow switch: a gas-flow switch changes contact state for a specified gas-flow condition.","description":["This reference locates gas flow switch in Autodesk's IEEE-oriented miscellaneous switches family. A gas-flow switch changes contact state for a specified gas-flow condition. Its process connection and operating requirement belong in the equipment schedule as well as the control logic. The public library uses HFS11S20 for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number.","Read the operating mechanism and the contact reference state together. Cross-reference every associated contact to the same device and show which movement, signal or reset changes its condition; the symbol alone does not establish the complete switching sequence.","Do not substitute liquid-flow characteristics for the selected gas device. Gas-flow actuation is a process-specific input and is separate from the contact's electrical rating. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted."],"readingNotes":["Do not substitute liquid-flow characteristics for the selected gas device.","The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation."],"drawingChecklist":["Identify gas service","Record operating condition","Reference contact and reset action"],"distinction":"Gas-flow actuation is a process-specific input and is separate from the contact's electrical rating.","facts":[{"label":"Convention evidence","value":"Autodesk IEEE Symbol Preview: Miscellaneous Switches; published form: Flow Switch Normally Open - Gas."},{"label":"Public vendor block","value":"HFS11S20. Vendor library token, not an IEEE symbol number."},{"label":"Drawing role","value":"Actuated indication"},{"label":"Identifier status","value":"The short label is a functional lookup label, not an assigned IEC or IEEE symbol number. Any separately listed Autodesk code is a verified vendor block name."},{"label":"Artwork scope","value":"Original educational geometry. Exact standard graphics, product ratings and terminal pinouts are not certified."}],"references":[{"sourceId":"ansi-autodesk-278f6c21-b1a6-4ea1-a535-e78d53bbd10d","relevance":"Public IEEE-oriented Miscellaneous Switches table explicitly lists HFS11S20 as Flow Switch Normally Open - Gas. This supports the vendor convention context, not reproduction of the publisher graphic."}],"related":["gas-flow-switch","plc-io","normally-open-contact"],"artwork":"s28-ansi-gas-flow-switch","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEEE / ANSI","form":"Flow Switch Normally Open - Gas","reference":"Autodesk IEEE Symbol Preview: Miscellaneous Switches, block HFS11S20. Matching functional counterpart linked separately. Independently drawn educational geometry; not a certified IEEE glyph or database identifier.","counterpart":"gas-flow-switch"},"plainEnglish":{"title":"What does ANSI/IEEE Gas flow switch form mean?","introduction":"This reference locates gas flow switch in Autodesk's IEEE-oriented miscellaneous switches family. A gas-flow switch changes contact state for a specified gas-flow condition. Its process connection and operating requirement belong in the equipment schedule as well as the control logic. The public library uses HFS11S20 for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number.","example":"Read the operating mechanism and the contact reference state together. Cross-reference every associated contact to the same device and show which movement, signal or reset changes its condition; the symbol alone does not establish the complete switching sequence.","drawings":"Do not substitute liquid-flow characteristics for the selected gas device. Gas-flow operation is a process-specific input and is separate from the contact's electrical rating. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted.","terms":[{"name":"Normally open / normally closed","meaning":"The contact state in the normal condition defined for the drawing."},{"name":"Terminal","meaning":"An identified point where a conductor connects."},{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"Autodesk IEEE Symbol Preview — Miscellaneous Switches","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-278F6C21-B1A6-4EA1-A535-E78D53BBD10D.htm"}],"detail":"IEEE-library form of gas flow switch: a gas-flow switch changes contact state for a specified gas-flow condition. Gas-flow operation is a process-specific input and is separate from the contact's electrical rating.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/ansi-gas-flow-switch","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/ansi-gas-flow-switch.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"ansi-autodesk-278f6c21-b1a6-4ea1-a535-e78d53bbd10d","title":"Autodesk IEEE Symbol Preview — Miscellaneous Switches","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-278F6C21-B1A6-4EA1-A535-E78D53BBD10D.htm","type":"cad-reference","scope":"Verified public IEEE-oriented vendor catalogue. Block names identify vendor symbols, not IEEE standard symbol numbers. Linked only; graphics and CAD files are not redistributed. IEEE/ANSI 315-1975 is a historical graphics reference with Inactive-Reserved status; this page does not certify current standards compliance.","checkedOn":"2026-10-14","reuse":"link-only","relevance":"Public IEEE-oriented Miscellaneous Switches table explicitly lists HFS11S20 as Flow Switch Normally Open - Gas. This supports the vendor convention context, not reproduction of the publisher graphic."}]}