Clocks

1. Scope and Applicability

This PCR applies to complete, non-wearable clocks whose principal function is to indicate time of day. It covers analog or digital alarm, wall, table, mantel, instrument-panel, and other complete clocks, whether electrically operated or not, when the foreground dataset declares the mechanism, display, accuracy specification, power interface, supplied battery state, and manufacturing route.

It excludes wearable watches; time-recording, interval-measuring, time-switching, or similar apparatus whose principal function is not ordinary time-of-day indication; watch or clock movements sold separately; other clock parts sold separately; and multifunction products whose principal product identity is a radio, telephone, computer, appliance, vehicle, or other non-clock product. Distribution, consumer use, maintenance, replacement batteries, and end-of-life are outside the default factory-gate boundary.

The representative route is assembly and calibration of an analog quartz table clock from a purchased clock movement, complete clock case, analog clock dial, and a button-cell battery supplied with the clock. Other covered clock technologies remain eligible only when their concrete component exchanges and required qualifiers are declared without substituting collection labels for atomic flows.

2. Product Category Identity

Field	Value
canonical_pcr_id	pcr.metal-products-machinery-and-equipment.medical-appliances-precision-and-optical-instruments-watches-and-clocks.clocks
classification_refs	CPC 3.0: 48420, Clocks (exact)
covered_products	Complete non-wearable clocks principally indicating time of day, including alarm, wall, table, mantel, instrument-panel, analog, digital, electrically operated, and non-electrically operated clocks
excluded_products	Watches; time-recording, interval-measuring, and time-switching apparatus; separately sold watch or clock movements; separately sold clock parts; products whose principal identity is not a clock
representative_product	Analog quartz table clock with one supplied button-cell battery
production_route	Receipt of purchased clock movement, complete clock case, analog clock dial, and included battery; assembly; calibration; functional testing; release of conforming clock at the factory gate before sales packaging
market_state	Complete, tested, unpackaged clock at the manufacturing factory gate; mechanism, display, accuracy specification, power interface, and included-battery state declared

3. Reference Flow

Field	Value
What	A complete non-wearable clock providing ordinary time-of-day indication
How much	1 kg of conforming clocks at the declared factory-gate state
How well	Meets the producer's declared timekeeping accuracy, display readability, functional-test acceptance criteria, and power-interface specification
How long or cycle	Declared design service life under the stated duty pattern; service life is a required qualifier and is not embedded in the 1 kg manufacturing reference amount
reference_flow_link	The mass of conforming complete clocks released by final_clock_assembly and normalized to 1 kg

Field	Value
Reference amount	1 kg
Reference product flow	Clocks 24759480-c6f3-43e9-90be-61582a11d717
Reference flow property	Mass 93a60a56-a3c8-11da-a746-0800200b9a66
Reference unit group	Units of mass 93a60a57-a4c8-11da-a746-0800200c9a66
Reference unit	kg
Required qualifiers	clock type and intended installation; mechanism and time base; analog or digital display; declared accuracy and test method; power interface; supplied battery chemistry, format, count, and inclusion state; complete-clock net mass excluding sales packaging; factory-gate state; manufacturing geography and technology; data period; declared design service life and duty pattern

When constructing a foreground data package, the items listed in Required qualifiers must be declared in dataset metadata, process notes, reference flow comment, product description, or an equivalent data package field. Missing required qualifiers make the reference flow definition incomplete for that data package.

4. Measurement and Unit Rules

rule_id	Applies to	Required property	Required unit	Rule
reference_clock_mass	reference product	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg	Measure net mass of conforming complete clocks after calibration and testing and before sales packaging; exclude pallets, reusable transport items, and sales packaging from the reference-product mass.
component_mass_normalization	clock movement, clock case, analog clock dial, and included battery	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg/kg	Record each received component separately by mass and divide the accepted batch quantity by the conforming complete-clock mass from the same batch.
electricity_energy_conversion	assembly electricity	Net calorific value 93a60a56-a3c8-11da-a746-0800200b9a66	MJ	Preserve metered kWh in raw records and convert to MJ using 1 kWh = 3.6 MJ before normalization; do not add upstream grid emissions as foreground elementary flows.
defect_mass_consistency	defective complete clock waste	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg/kg	Weigh rejected complete clocks before dismantling or rework; do not combine component scrap, packaging waste, or mixed manufacturing waste with this row.

5. System Boundary

The default boundary begins when purchased clock components and supplied batteries enter the reporting facility and ends when conforming, tested clocks are released at the factory gate before sales packaging. It includes component receipt and internal handling, assembly, calibration, functional testing, electricity used by those operations, and management of defective complete clocks. Upstream production of purchased components and electricity is represented by linked upstream datasets rather than repeated as foreground exchanges.

Boundary Abstraction

Field	Value
declared_starting_condition	Purchased clock movement, complete clock case, analog clock dial, and any battery supplied with the clock at the reporting facility receiving point
starting_condition_role	Auditable gate-to-gate starting condition for the declared clock-assembly route
product_classification_scope	Complete clocks within CPC 3.0 subclass 48420; watches, time-recording apparatus, separately sold movements, and separately sold parts are outside the canonical product boundary
recursive_input_rule	A purchased complete clock used as an input must be represented by a separately identified upstream clock dataset and must not be silently decomposed or counted again inside the current assembly process
upstream_dataset_requirement	Link geographically and technologically representative upstream datasets for every purchased component, battery, and electricity input; disclose any proxy and its effect on completeness
disclosure	Declare the starting condition, component make-or-buy boundary, clock mechanism, display, supplied battery state, included operations, excluded operations, reference-product mass convention, geography, technology, and data period

rule_id	Applies to	Rule	source_ids
boundary_clock_identity	product scope	Apply this PCR only when the reference product is a complete clock whose principal identity is ordinary time-of-day indication within CPC 3.0 subclass 48420.	un-cpc-3-0-structure-2025
boundary_factory_gate	foreground operations	Include receipt, internal handling, assembly, calibration, functional testing, electricity used by those operations, and defective complete-clock handling through release at the factory gate before sales packaging.
boundary_upstream_links	purchased inputs	Represent production of purchased movements, cases, dials, supplied batteries, and electricity with linked upstream datasets and do not duplicate their upstream exchanges in the foreground inventory.
boundary_default_exclusions	excluded life-cycle stages	Exclude sales packaging, distribution, consumer use, maintenance, replacement batteries, and end-of-life unless a study explicitly extends the boundary and reports those stages separately.

6. Process Inventory Structure

Process Map

process_id	process_name	inclusion	inclusion_condition	role	quantitative_reference
final_clock_assembly	Final clock assembly, calibration, and testing	required	Applies to every dataset using this factory-gate PCR	Foreground manufacturing process that converts purchased components into conforming complete clocks	1 kg conforming complete clocks before sales packaging

Process: Final clock assembly, calibration, and testing (final_clock_assembly)

Inputs

Product flows

Purchased timekeeping movement (clock_movement)

The complete purchased movement crosses the receiving boundary and provides the time base and drive function for the representative clock. Record only the movement delivered to assembly, not its internal gears or electronic parts again.

• Selected flow: Watch or clock movements 3dcf3381-920e-4477-a31c-aa2594aa8c59
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg
• Amount rule: measured accepted movement mass issued to the assembly batch
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming complete-clock output before sales packaging
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_component_receipts
• Sources:

Complete clock case (clock_case)

The complete case that houses and supports the representative clock crosses the receiving boundary as one product input. Material, finish, dimensions, supplier, and fit must be declared; its exact Tiangong flow UUID remains unresolved.

• Selected flow: Clock case
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg
• Amount rule: measured accepted clock-case mass issued to the assembly batch
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming complete-clock output before sales packaging
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_component_receipts
• Sources:

Analog clock dial (analog_clock_dial)

The finished analog dial or face crosses the receiving boundary and provides the visible time scale for the representative product. Record it separately from the case and movement; its exact Tiangong flow UUID remains unresolved.

• Selected flow: Analog clock dial
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg
• Amount rule: measured accepted dial mass issued to the assembly batch
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming complete-clock output before sales packaging
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_component_receipts
• Sources:

Battery supplied with the clock (included_button_cell_battery)

Record one new button-cell battery only when it is physically supplied with the representative clock at the declared factory-gate state. Battery-free products must document that this exchange is absent rather than substituting use-phase replacement batteries; the exact Tiangong flow UUID remains unresolved.

• Selected flow: Button-cell battery
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg
• Amount rule: measured mass of new button-cell batteries installed in or supplied with the conforming batch; absent only when the dataset declares that no battery is supplied
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming complete-clock output before sales packaging
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_component_receipts
• Sources:

Electricity used for assembly and testing (assembly_electricity)

Electricity crosses the foreground boundary through assembly-line, calibration-bench, test-rig, and directly attributable support loads. Grid mix, voltage, geography, losses, and meter allocation must be declared.

• Selected flow: Electricity 67b723a9-6f63-4802-adca-b52ce7967d47
• Flow property / unit: Net calorific value 93a60a56-a3c8-11da-a746-0800200b9a66 / MJ
• Amount rule: metered electricity attributable to the assembly batch, converted from kWh to MJ and normalized to conforming output
• Value mode: Calculated value (calculated_value)
• Specificity: Site-specific (site_specific)
• Normalization basis: per 1 kg conforming complete-clock output before sales packaging
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Calculated from collection (calculated_from_collection)
• Collection protocol: cp_assembly_electricity
• Sources:

Waste flows

Elementary flows

Outputs

Product flows

Conforming complete clock (clock_output)

Conforming complete clocks leave assembly after calibration and functional testing. Their net mass establishes the reference output and excludes sales packaging.

• Selected flow: Clocks 24759480-c6f3-43e9-90be-61582a11d717
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg
• Amount rule: exactly 1 kg after normalization from measured conforming batch output
• Value mode: Calculated value (calculated_value)
• Specificity: Product-specific (product_specific)
• Normalization basis: 1 kg conforming complete-clock reference flow before sales packaging
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Calculated from collection (calculated_from_collection)
• Collection protocol: cp_clock_output
• Sources:

Waste flows

Defective complete clocks (defective_complete_clock)

Complete clocks rejected after assembly or functional testing cross the process boundary as a distinct waste stream when they are not reworked in the same batch. Do not combine them with component scrap or mixed manufacturing waste; the exact Tiangong waste-flow UUID remains unresolved.

• Selected flow: Defective complete clock
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg
• Amount rule: measured mass of rejected complete clocks leaving the process for treatment, excluding units fully reworked into conforming output in the same batch
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per 1 kg conforming complete-clock output before sales packaging
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_defective_clock_waste
• Sources:

Elementary flows

No direct elementary exchange is prescribed for the representative assembly route. Any measured direct release from a site-specific added operation must be represented as its own chemically specific elementary-flow row rather than as an umbrella emission category.

7. Allocation and Co-product Handling

rule_id	Applies to	Rule	source_ids
allocation_subdivision_first	shared assembly, calibration, and testing operations	Avoid allocation by separately metering or otherwise subdividing product-line electricity, component issues, conforming output, and defective-clock waste wherever practicable.
allocation_physical_mass	inseparable shared operations producing more than one clock model	When subdivision is not practicable, allocate shared burdens among clock models by measured conforming product mass; disclose the affected operations, models, allocation denominator, and sensitivity to an item-count alternative.
allocation_no_defect_credit	defective complete clocks	Assign burdens incurred before rejection to the production batch and report the defective-clock waste output without an avoided-product credit; model any recycling or treatment in the linked downstream waste dataset.

8. Foreground Data Collection, Calculation, and Quality Rules

Data Collection Protocols

protocol_id	process_id	flow_role	record_type	raw_fields	collection_method	unit	frequency	temporal_coverage	site_scope	aggregation_rule	quality_evidence
cp_component_receipts	final_clock_assembly	purchased component input	receiving and issue records plus verified mass measurement	supplier; SKU; component description; movement mechanism; case material and finish; dial type; battery chemistry and format; accepted count; rejected count; tare mass; net mass; batch_id	Reconcile receiving and line-issue records; verify representative unit or lot mass with a calibrated balance; retain component identity by row_id	kg	Each received lot and assembly batch	Same reporting period as clock output, normally at least 12 consecutive months	All component lots used by the reporting facility for the declared clock product	Sum accepted net mass issued to the batch by atomic component row and divide by conforming clock output mass	Purchase/issue reconciliation, supplier specification, balance calibration record, and sampled weighing record
cp_assembly_electricity	final_clock_assembly	assembly electricity input	submeter or documented meter allocation	meter_id; opening_kWh; closing_kWh; timestamps; production-line operating hours; shared-load allocation basis; batch_id	Read dedicated submeters where available; otherwise allocate a documented parent-meter difference using measured operating hours or equipment load-hours	kWh and MJ	At least monthly and for each production campaign when campaign data exist	Same reporting period as clock output, normally at least 12 consecutive months	Assembly, calibration, testing, and directly attributable support equipment at the reporting facility	Subtract verified non-production loads, convert kWh to MJ, sum the reporting period, and divide by conforming clock output mass	Meter identification, calibration or utility reconciliation, reading log, and allocation worksheet
cp_clock_output	final_clock_assembly	conforming clock product output	production release and mass records	model; mechanism; display; accuracy specification; power interface; supplied battery state; accepted_count; net_unit_mass; total_conforming_mass; release_date; batch_id	Reconcile quality-release counts with calibrated net-mass measurements after testing and before sales packaging	kg	Each released batch	Same period as all input and waste records, normally at least 12 consecutive months	All conforming clock output from the declared line and product system	Sum conforming net clock mass; use it as the denominator and scale all exchanges to exactly 1 kg	Quality-release record, test acceptance record, balance calibration, and batch reconciliation
cp_defective_clock_waste	final_clock_assembly	defective complete-clock waste output	rejection, rework, weighing, and dispatch records	rejected_count; defect_code; gross_mass; tare_mass; net_mass; rework_status; destination; dispatch_reference; batch_id	Weigh complete rejected clocks before dismantling or dispatch and reconcile units reworked into conforming output	kg	Each batch and each waste dispatch	Same reporting period as clock output, normally at least 12 consecutive months	All complete-clock rejects generated by the declared process	Sum net mass dispatched as waste; exclude successfully reworked clocks and normalize by conforming clock output mass	Rejection log, rework reconciliation, calibrated weighing record, and waste transfer evidence

Calculation Rules

rule_id	Applies to	Formula or rule	Inputs	Output	source_ids
calc_mass_normalization	all mass-based input and waste rows	normalized amount (kg/kg) = batch atomic-flow net mass (kg) / conforming complete-clock net mass (kg)	batch row mass; conforming clock output mass; matched batch_id and period	kg exchange per kg conforming complete clocks
calc_electricity_mj	assembly_electricity	normalized electricity (MJ/kg) = attributable electricity (kWh) × 3.6 / conforming complete-clock net mass (kg)	verified meter difference; excluded load; allocation factor; conforming output mass	MJ electricity per kg conforming complete clocks
calc_clock_output_reference	clock_output	Divide measured conforming complete-clock mass by itself after confirming a positive denominator; the normalized reference output equals exactly 1 kg	measured conforming complete-clock mass	1 kg reference product
calc_clock_mass_balance	final clock assembly mass balance	Compare atomic component inputs with conforming clock output, defective complete-clock waste, documented in-process inventory change, and separately recorded atomic component scrap; investigate unexplained mass rather than forcing closure	atomic component masses; output mass; defective-clock waste; in-process inventory change; separately identified scrap	disclosed mass-balance difference and reconciliation status

Data Quality Requirements

requirement_id	Applies to	Requirement	Evidence
dq_product_identity	reference product	Retain model, mechanism, display, accuracy specification, power interface, supplied battery state, net mass convention, and factory-gate state sufficient to demonstrate that the output is a complete clock rather than a watch, movement, part, or time-recording apparatus.	Product specification, bill of materials, product photograph or drawing, and quality-release record
dq_flow_identity	every inventory row	Preserve one concrete exchange identity per row, the selected Tiangong UUID when confirmed, property and unit, supplier or meter context, and any unresolved UUID status; do not aggregate unlike components, wastes, or emissions.	Row-level reconciliation and UUID review record
dq_temporal_alignment	all foreground data	Use the same representative period for input, output, electricity, and waste records; disclose shutdowns, launches, abnormal campaigns, and any period shorter than 12 consecutive months.	Dated source records and reporting-period reconciliation
dq_measurement	mass and electricity records	Use calibrated or verified balances and meters, retain tare corrections and conversion worksheets, and document shared-meter allocation assumptions.	Calibration certificates or checks, raw readings, invoices, and calculation workbook
dq_completeness	foreground inventory	Reconcile purchased component issues, conforming output, defective-clock waste, rework, in-process inventory change, and electricity coverage; quantify any excluded or estimated share.	Mass-balance statement, energy reconciliation, and completeness checklist

9. Validation Rules

rule_id	Applies to	Rule	source_ids
validate_clock_identity	product identity	Confirm that the reference product is a complete non-wearable clock in CPC 3.0 subclass 48420 and not a watch, time-recording apparatus, separately sold movement, separately sold part, or multifunction product with another principal identity.	un-cpc-3-0-structure-2025
validate_reference_flow	reference flow	Require a positive conforming complete-clock mass and a normalized clock_output of exactly 1 kg using the declared net-mass convention.
validate_required_qualifiers	dataset metadata	Reject an incomplete reference-flow definition when any required qualifier in section 3 is missing or when the supplied battery state is inconsistent with included_button_cell_battery.
validate_atomic_inventory	process inventory	Require every material, battery, electricity, waste, and any added direct-emission exchange to use its own row, property, unit, amount rule, protocol, and identity status.
validate_period_reconciliation	foreground records	Confirm that component, electricity, conforming output, reject, rework, and in-process inventory records cover the same declared period and facility scope.
validate_mass_balance	assembly mass balance	Report the mass-balance difference from calc_clock_mass_balance; investigate and disclose component scrap, stock change, moisture, and measurement uncertainty rather than hiding an unexplained difference.

10. Published Dataset Profile

Field	Value
dataset_role	Foreground clock-manufacturing data package and product-category-specific process dataset
downstream_use	secondary_dataset; background_dataset after methodology review, geographic and technological representativeness review, and resolution or explicit acceptance of open identity and range-evidence needs
allowed_use	Comparative or attributional modelling of complete clocks that match the declared mechanism, display, accuracy, power interface, supplied battery state, factory-gate state, geography, technology, and data period
excluded_use	Watches, separately sold movements or parts, time-recording apparatus, packaged-clock claims, distribution, use-phase energy or batteries, maintenance, and end-of-life without explicit additional modelling
required_metadata	PCR id and version; product model and clock type; mechanism and time base; display; accuracy specification and test method; power interface; battery chemistry, format, count, and supplied state; net mass convention; facility geography and technology; make-or-buy boundary; data period; allocation; upstream dataset identities; unresolved UUIDs; exclusions
required_quality_disclosure	Primary-data share; meter and balance coverage; calibration status; temporal coverage; shared-load allocation; component and output reconciliation; defect and rework treatment; mass-balance difference; proxy datasets; unresolved UUIDs and range-evidence needs
update_trigger	Change in mechanism, display, case or dial design, supplied battery, assembly technology, facility, electricity supply, make-or-buy boundary, allocation, net-mass convention, or data period; resolution of an identity or range-evidence need; or a material change in normalized inputs, electricity, output, or waste

11. Data Sources

Source id	Type	Reference	Used for
un-cpc-3-0-structure-2025	Official guidance (official_guidance)	United Nations Statistics Division, Central Product Classification Version 3.0, structure dated 30 June 2025, https://unstats.un.org/unsd/classifications/Econ/Download/In%20Text/CPC_Ver_3.0_Structure_30Jun2025.csv (retrieved 2026-09-07)	Official CPC 48420 identity and separation from watches, time-recording apparatus, movements, and other parts
un-cpc-1-1-chinese-2002	Official guidance (official_guidance)	United Nations Statistics Division, Central Product Classification Version 1.1, Chinese edition, https://unstats.un.org/unsd/publication/SeriesM/M_77ver1_1c.pdf (retrieved 2026-09-07)	Verified professional Chinese category term “钟” and distinction from “表”, “钟表机心”, and other parts