weather vane

Wind-responsive assembly

Record the pivoted assembly and evidence that it was intended to indicate wind direction, even if it no longer moves.

1. Which parts rotate in response to airflow, and which remain fixed? definition
2. What construction evidence or documentation distinguishes this object from a fixed ornament, windsock or anemometer? boundary

Pointer and reference

Record the intended indicating end, whether the reading means wind-from or wind-toward, and the reference against which orientation is read.

1. Which end or feature is intended to be read, and what evidence establishes its wind-from or wind-toward convention? provenance
2. Are directions referenced to true north, magnetic north or a local datum, and how was marker alignment verified? measurement

Rotation obstructions

Record sticking, bearing wear, contact with fixed parts and temporary obstruction by ice, debris or vegetation.

1. Does the assembly move through its intended rotation without rubbing, binding or striking compass markers or nearby surfaces? measurement
2. What safe inspection or documented test can distinguish weak airflow from pivot resistance? action

Shape, balance and following

Record deformation, missing parts, tilt and observed response to changing airflow without assuming universal performance thresholds.

1. Are the pointer, tail or shaped body complete and positioned as intended, and is there evidence of imbalance or a tilted pivot? measurement
2. Under documented airflow conditions, does the vane follow direction changes, remain stuck or oscillate without a usable reading? measurement

Local wind representativeness

Record installation height and surrounding geometry in relation to the location whose wind direction is of interest.

1. Where is the vane relative to roof ridges, walls, trees and other nearby obstructions? measurement
2. Is the intended reading about airflow at the vane, around the building or across a wider site, and what supports that interpretation? boundary

Time-bound direction reading

Record direction, time, viewing limitations and whether current movement supports treating the orientation as a live indication.

1. What direction was observed, at what time, using which reference and with what angular or sector uncertainty? measurement
2. Does visible movement or an independent airflow observation support this reading, or could it be a retained orientation during calm or obstruction? measurement

Attachment condition

Record loose fasteners, failed joints, corrosion and missing retainers at the vane and its immediate support interface.

1. Are the rotating body, compass arms, shaft and mounting fasteners retained securely, and what evidence supports that assessment? measurement
2. Which observed defects require restricting access below, securing loose parts or referring the supporting structure for separate assessment? action

Maintenance and reverification

Record design-specific maintenance instructions, access constraints and post-work checks of movement, retention and directional alignment.

1. What documented instructions and material or conservation constraints govern cleaning, lubrication, straightening or replacement of this vane's parts? provenance
2. After intervention, which checks establish secure retention, unobstructed rotation and correct directional interpretation? action

Kinds and varieties

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• architectural or ornamental weather vane (silhouette figures on roofs, barns, and towers)
• weathercock (rooster-form vane, historically the dominant church type)
• meteorological wind vane (instrument-grade direction sensor, often with a potentiometer, encoder, or Hall sensor)
• aerovane or propeller-vane (combined direction and speed head)
• masthead sailing vane (lightweight pointer such as a Windex-type indicator)
• wind-vane self-steering gear (yacht servo that uses a vane to actuate the rudder or a trim tab)
• banner or pennant vane (cloth or thin plate that streams rather than a rigid counterweighted figure)
• remote-indicating or transmitting wind vane (electrical or wireless readout to a display or logger)

1. Which of these kinds and varieties hold for the sense of weather vane this model covers, and on what evidence? provenance

Identifiers and schemes

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Wikidata - Q5356094 - Item commonly used for weather vane / wind vane; confirm against the sitelink on the English Wikipedia article before treating the Q-id as canonical.
• Getty Art & Architecture Thesaurus (AAT) - weather vanes - Preferred AAT term for the object type in museum and historic-building catalogues; use the current AAT numeric id from the Getty vocabulary service rather than a memorised number.
• WMO / CIMO instrument class - wind vane (wind-direction sensor) - Treated in WMO-No. 8 as a wind-direction instrument, often logged with an anemometer as a combined wind sensor.

1. Which of these identifiers and schemes hold for the sense of weather vane this model covers, and on what evidence? provenance

Standards and regulation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• WMO-No. 8 Guide to Instruments and Methods of Observation - World Meteorological Organization (performance, siting, and exposure of wind-direction sensors).
• EPA-454/R-99-005 Meteorological Monitoring Guidance for Regulatory Modeling Applications - U.S. Environmental Protection Agency (regulatory wind-vane siting and accuracy).
• ASTM D5741 - ASTM International (characterising surface wind with a wind vane and rotating anemometer).
• ICAO Annex 3 (Meteorological Service for International Air Navigation) and Annex 14 (Aerodromes) - International Civil Aviation Organization (aerodrome wind-direction information; windsocks are specified separately).
• IEC 61400-12-1 - International Electrotechnical Commission (wind vanes used in wind-turbine power-performance testing).
• NFPA 780 / equivalent national lightning-protection codes - often relevant because a metal roof vane can form part of, or interfere with, a lightning-protection system.
• National building and listed-building rules (e.g. IBC rooftop appurtenances; historic-church fabric consents) - govern mounting, load, and alteration of architectural vanes.

1. Which of these standards and regulation hold for the sense of weather vane this model covers, and on what evidence? provenance

Real-world use

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Roof and tower ornaments on churches, barns, public buildings, and houses, read by eye as a local wind-direction cue and as a decorative finial.
• Synoptic, climatological, and air-quality stations, where a vane (or combined wind sensor) supplies the direction component of the wind record.
• Airfields and heliports as a visual or instrument wind-direction source (alongside or distinct from a windsock).
• Small-craft sailing, where a masthead vane is used for apparent-wind angle while racing or trimming.
• Ocean-going yachts, where a wind-vane self-steering gear holds a course relative to the wind without an electric autopilot.
• Wind-turbine nacelles, where a vane (or equivalent direction sensor) feeds yaw control.
• Antique and folk-art markets, especially North American nineteenth-century figural vanes treated as sculpture rather than instruments.

1. Which of these real-world use hold for the sense of weather vane this model covers, and on what evidence? provenance

Typical measurements

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• indicated wind direction (meteorological, direction from which the wind blows) - 0-360 - degree
• starting threshold (lowest wind speed at which the vane aligns usefully) - 0.5-1.5 - m/s
• direction accuracy (quality meteorological vanes; WMO operational target around 5°) - ±3 to ±5 - degree
• damping ratio - 0.3-0.7 - 1 (dimensionless)
• delay or distance constant - 1-10 - m
• standard meteorological mounting height above ground - 10 (open site; often lower on ships and rooftops) - m
• vane body length (instrument heads versus architectural figures) - 0.3-1.2 (instruments); 0.3-2 (typical architectural) - m

1. Which of these typical measurements hold for the sense of weather vane this model covers, and on what evidence? provenance

Failure modes and hazards

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Bearing seizure from ice, corrosion, dust, or dried lubricant, so the pointer sticks and reports a false constant direction.
• Mount not surveyed to true north (or to a documented reference meridian), producing a systematic azimuth bias in logged data.
• Underdamping: the vane overshoots and oscillates in gusts; overdamping: it lags and under-reads direction changes.
• Exposure error: building wakes, roof edges, trees, or masts distort the local flow so a correctly working vane still reports unrepresentative direction.
• Lightning strike or bonding failure on a metal roof vane; also a falling-object hazard if the figure, shaft, or brackets fatigue.
• Encoder, potentiometer, or cable failure on transmitting vanes (dead band, wrap-around glitch at north, or stuck bits).
• Bird perching or nesting that unbalances or jams the vane.
• Misreading the convention: reporting direction the wind is going to, rather than coming from.

1. Which of these failure modes and hazards hold for the sense of weather vane this model covers, and on what evidence? provenance

Regional variation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• English usage: 'weather vane' or 'weathervane' is general; 'weathercock' in British and older church usage often means a rooster-form vane specifically.
• French girouette, German Wetterfahne, Dutch weerhaan, Japanese kazamidori (the Kobe/Kitano weathercock is a well-known local landmark type).
• Western Christian churches favoured the rooster after a medieval papal association of the cock with St Peter; other figures (ships, fish, banners, trades) are common on secular buildings.
• United States: a strong nineteenth-century New England folk-art tradition of copper figural vanes (horses, eagles, cows, locomotives) that is now collected as sculpture.
• Official meteorology everywhere treats the device as a wind-direction sensor and usually pairs it with an anemometer; architectural practice treats it as a finial whose accuracy is secondary.

1. Which of these regional variation hold for the sense of weather vane this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• windsock (wind cone) - A windsock is a fabric tube that droops or lifts with speed and streams downwind; a weather vane is a pivoted rigid (or stiff) pointer. ICAO aerodrome kit specifies windsocks separately from direction vanes.
• anemometer - An anemometer measures wind speed; a vane measures direction. Combined heads exist (aerovane, propeller-vane), but a cup or sonic anemometer alone is not a vane.
• flag or banner - A flag streams from a halyard and is not a balanced rotator with a defined pointer and a 360° scale; some early 'banner vanes' sit on the boundary.
• lightning rod or roof finial - A finial or air terminal is fixed; a vane must rotate. Many historic church fittings combine a cock vane with a lightning conductor - test by whether the figure turns.
• wind-vane self-steering gear - Shares a wind-sensing paddle but is an actuator that couples to the tiller, rudder, or a trim tab to hold a sailing course, not merely an indicator.
• wind rose - A wind rose is a diagram or compass card of directional frequencies, not the physical sensor.
• ultrasonic or lidar wind sensor - Derives direction from time-of-flight or Doppler without a rotating aerodynamic pointer; no mechanical vane to seize, but different calibration and icing behaviour.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of weather vane this model covers, and on what evidence? provenance