Fire Protection Symbols Guide
Fire protection drawings use a standardized set of symbols to represent sprinkler heads, valves, alarm devices, and piping runs across FP (Fire Protection) and E (Electrical) sheets. This guide covers the most common fire suppression symbols, fire alarm device symbols, valve types, and piping abbreviations found on commercial construction documents.
Fire Suppression Symbols
These symbols appear on FP (Fire Protection) sheets and represent the physical components of the fire sprinkler and standpipe systems — including sprinkler heads, pipe connections, flow switches, tamper switches, and fittings.
Remove to Point for Reconnection
Indicates a pipe segment that should be removed back to the nearest connection point and reconnected to the new layout.
Remove to Point and Cap
Marks a pipe run to be cut back to a specified point and capped off permanently.
Check Valve
A one-directional valve that prevents backflow in the fire suppression piping system.
Backflow Preventer
Prevents contaminated water from flowing back into the potable water supply. Required at fire service connections.
Flow Switch
Detects water movement in the sprinkler piping and sends a signal to the fire alarm panel when flow is detected.
Tamper Switch
Monitors the position of a control valve and sends a supervisory signal to the fire alarm panel if the valve is moved from its normal position.
Union
A fitting that allows two pipe sections to be joined and later disconnected without cutting, used for maintenance access.
Pipe Branch Take-Off from Bottom
A branch connection that exits from the underside of a main pipe run.
Pipe Branch Take-Off from Top
A branch connection that exits from the top of a main pipe run.
Pipe Drop
A vertical pipe section that drops down from a horizontal run to feed a lower level or a sprinkler head below.
Pipe Rise
A vertical pipe section that rises up from a horizontal run to feed an upper level or riser.
Concealed / Semi-Recessed Sprinkler Head
A sprinkler head that is flush-mounted or partially concealed within the ceiling for a cleaner appearance while maintaining fire suppression capability.
Upright Sprinkler Head
A sprinkler head installed in the upright position above the branch line, typically used in mechanical rooms, warehouses, and areas without finished ceilings.
Pendent Sprinkler Head
A sprinkler head that hangs down from the branch line below the ceiling — the most common type in finished commercial and residential spaces.
Sidewall Sprinkler Head
A sprinkler head mounted on a wall rather than the ceiling, used in corridors, small rooms, and areas where ceiling-mounted heads are not practical.
Fire Alarm Device Symbols
Fire alarm symbols appear on E (Electrical) sheets and represent the detection, notification, and control devices that make up the fire alarm and life safety system. Mounting heights are typically specified as AFF (Above Finished Floor) and UON (Unless Otherwise Noted).
FAAP
Fire Alarm Annunciator Panel
Wall-mounted panel (typically at 60" AFF to center) that displays the status and location of alarm zones throughout the building.
FACP
Fire Alarm Control Panel
The central brain of the fire alarm system, wall-mounted at 60" AFF to top. Receives signals from initiating devices and activates notification appliances.
FA Pull
Fire Alarm Pull Station
Manual pull station mounted at 48" AFF allowing building occupants to manually activate the fire alarm system in an emergency.
■ (speaker)
Fire Alarm Speaker — Wall Mounted
Audio notification appliance mounted on the wall at 60" AFF to the bottom of the device for voice evacuation and alarm tones.
■ (speaker/ceil)
Fire Alarm Speaker — Ceiling Mounted
Audio notification appliance installed in the ceiling grid or surface-mounted to the ceiling structure.
○ (smoke)
Fire Alarm Smoke Detector — Ceiling Mounted
Photoelectric or ionization smoke detector installed on the ceiling to detect products of combustion and initiate an alarm signal.
○ (duct)
Fire Alarm Duct Detector — Ceiling Mounted
Smoke detector installed in or near an HVAC duct to detect smoke being circulated through the air handling system and shut down airflow.
△ (heat/wall)
Fire Alarm Heat Detector — Wall Mounted
Thermal detection device mounted on the wall at the height indicated on drawings, activated when ambient temperature exceeds a fixed threshold or rises rapidly.
△ (heat/ceil)
Fire Alarm Heat Detector — Ceiling Mounted
Thermal detection device installed on the ceiling, commonly used in kitchens, mechanical rooms, and parking garages where smoke detectors would cause false alarms.
AV
Fire Alarm Audio/Visual Device
Combination horn-strobe or speaker-strobe that provides both audible and visible notification. Rough-in box with bottom of visible lens no less than 80" AFF.
V
Fire Alarm Visual-Only Device
Strobe-only notification appliance mounted so the visible lens is at or above 80" AFF. Used in areas where audible notification is provided by separate speakers.
FP
Fire Alarm Primacell / Telephone Jack
Firefighter telephone jack at 60" AFF allowing fire department personnel to communicate with the fire alarm control panel location.
MDH
Fire Alarm Magnetic Door Holder
Electromagnetic device mounted at 7 feet AFF (unless otherwise noted) that holds fire-rated doors open during normal conditions and releases them upon alarm activation.
DHR
Fire Alarm Door Holder — Recessed (Stairs)
Recessed electromagnetic door holder used at stairwell entries, allowing doors to close automatically when the fire alarm system activates.
Valve Symbols
Valves control the flow, pressure, and direction of water throughout the fire suppression and plumbing systems. These symbols are found on both FP and P (Plumbing) sheets.
Balancing Valve
Used to regulate and balance water flow rates within the fire suppression and plumbing systems.
Backflow Preventer
Prevents reverse flow of potentially contaminated water into the clean water supply. Required by code at fire department connections.
Check Valve
Allows water to flow in one direction only, preventing backflow in supply and sprinkler lines.
Pressure Reducing Valve
Reduces high-pressure water supply to the required operating pressure for the fire suppression or plumbing zone.
Shut Off Valve
Manually operated valve used to isolate sections of piping for maintenance or emergency shutoff.
Strainer with Blowdown
Screens debris from the water supply and includes a blowdown connection for periodic cleaning.
Recirculating Hot Water Circuit Valve
Controls flow in the hot water recirculation loop to maintain water temperature at distant fixtures.
Piping Abbreviations
Piping abbreviations are printed alongside line symbols on plumbing and fire protection drawings to identify the type of fluid, service, or system each pipe carries. Different line patterns (solid, dashed, or coded) are used in combination with these labels.
FP
Fire Protection Piping
Main piping for the fire suppression system.
SP
Standpipe Piping
Vertical piping in stairwells and risers that provides hose connections for firefighting on each floor.
SPR
Sprinkler Piping
Branch piping that distributes water from the riser to individual sprinkler heads.
RD
Roof Drain/Gravity Vent
Drain assembly on the roof connected to the storm drainage system.
RDA
Roof Drain Above
Indicates the roof drain is located on the level above the current plan view.
VTR
Vent Through Roof
A vent pipe that terminates through the roof to the atmosphere.
HB
Hose Bib
A threaded outdoor faucet or valve connection for attaching a fire hose or garden hose.
CW
Cold Water Piping
Domestic cold water supply piping throughout the building.
HW
Hot Water Piping
Domestic hot water supply piping.
HWR
Hot Water Return Piping
Recirculating return line that keeps hot water available at fixtures without waiting for the line to heat up.
G
Gas Piping
Natural gas or propane piping supplying boilers, water heaters, and kitchen equipment.
DW
Distilled Water Piping
Purified water piping used in laboratories, medical facilities, and industrial processes.
S
Sanitary Sewer (Above Ground)
Gravity-fed waste piping above the ground floor slab.
SAN
Sanitary Sewer (Underground/Floor)
Gravity-fed waste piping below the slab or underground.
ST
Storm Sewer (Above Ground)
Storm water drainage piping above the ground floor slab.
V
Vent Piping
Piping that allows air into the drainage system to maintain proper trap seals and prevent siphonage.
ACW
Acid Waste Piping
Corrosion-resistant piping for chemical waste in labs and industrial facilities.
AV
Acid Vent Piping
Venting for acid waste systems, typically made from corrosion-resistant materials.
CA
Compressed Air Piping
Pressurized air distribution piping for pneumatic tools, controls, and medical air systems.
MG
Medical Gas Outlet
Outlet connection for medical gases such as oxygen, nitrous oxide, or medical air.
MA
Medical Air Piping
Clean, filtered compressed air piping used in healthcare facilities for patient care.
MV
Medical Vacuum Piping
Suction piping connected to a central vacuum system for medical applications.
O
Oxygen Piping
Dedicated piping for medical-grade or industrial-grade oxygen distribution.
NO
Nitrous Oxide Piping
Piping for nitrous oxide used as an anesthetic gas in medical and dental facilities.
N
Nitrogen Piping
Piping for nitrogen gas distribution, used in laboratories, hospitals, and industrial settings.
Frequently Asked Questions
What do fire suppression symbols look like on construction drawings?
Fire suppression symbols use geometric shapes and line patterns to represent components such as sprinkler heads (triangles and circles), valves (diamond shapes on pipe lines), flow switches (circles), tamper switches (squares), and various pipe connection types. They appear on FP (Fire Protection) sheets in the construction document set.
What is the difference between a flow switch and a tamper switch?
A flow switch detects water movement in the sprinkler piping and sends an alarm signal when water is flowing, indicating a sprinkler head has activated. A tamper switch monitors the position of a control valve and sends a supervisory signal if the valve is moved from its normal open position, alerting building management that the fire suppression system may be impaired.
What does FACP stand for on fire alarm drawings?
FACP stands for Fire Alarm Control Panel. It is the central hub of the fire alarm system that receives signals from initiating devices (smoke detectors, heat detectors, pull stations) and activates notification appliances (speakers, strobes). It is typically wall-mounted at 60 inches above finished floor (AFF) to the top of the panel.
What is AFF in fire protection drawings?
AFF stands for Above Finished Floor. It specifies the mounting height of devices measured from the completed floor surface. For example, fire alarm pull stations are typically mounted at 48" AFF, and audio/visual notification devices require the bottom of the visible lens to be no less than 80" AFF.
Related Resources
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Knowledge Base
Guides, references, symbols, abbreviations, and review checklists for AEC professionals.
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