Base metals or silver, clad with gold, not further worked than semi-manufactured

1. Scope and Applicability

This PCR covers factory-gate production of semi-manufactured base metal or silver having a wrought gold covering affixed to one or more surfaces by soldering, brazing, welding, hot rolling, or a similar mechanical means. It also covers base metal inlaid with gold when the product remains semi-manufactured. The category boundary follows the official CPC 3.0 identity and the legal meaning of metal clad with precious metal. Gold-plated, electroplated, vapour-deposited, painted, or otherwise thin-coated metal is outside this PCR because plating is not cladding. Finished jewellery, components with an article-specific function, gold-clad scrap, and metal clad with silver or platinum are also excluded.

The representative route is continuous roll bonding of copper strip and gold strip, including surface preparation, stacking, pressure rolling, route-specific thermal treatment, gauge finishing, surface finishing, slitting, inspection, and handling of process wastes. A foreground data package may represent another covered substrate or another legally qualifying cladding route, but it must name every actual material, energy, waste, and elementary exchange as its own atomic row. Upstream production of purchased metals, chemicals, fuels, electricity, and water is represented by linked datasets; downstream article manufacture, use, and end-of-life are outside the foreground boundary.

2. Product Category Identity

Field	Value
canonical_pcr_id	pcr.metal-products-machinery-and-equipment.basic-metals.base-metals-or-silver-clad-with-gold-not-further-worked-than-semi-manufactured
classification_refs	CPC 3.0: 41340
covered_products	Semi-manufactured base-metal or silver strip, sheet, plate, rod, wire, or comparable wrought form with a gold covering mechanically or metallurgically affixed to one or more surfaces; qualifying base metal inlaid with gold
excluded_products	Electroplated or otherwise merely plated/coated metal; solid or alloyed gold without a distinct substrate; metal clad with silver or platinum; finished articles and jewellery; gold-clad waste and scrap
representative_product	Gold-clad copper strip produced by solid-state roll bonding and delivered as inspected semi-manufactured coil or cut strip
production_route	Surface preparation, stacking, roll bonding, route-specific heat treatment, finish rolling, surface finishing, slitting, inspection, and packing; other qualifying soldered, brazed, welded, hot-rolled, or similar mechanical routes require explicit route disclosure
market_state	Dry, solid, unassembled semi-manufactured product at the factory gate, with declared substrate, gold layer, geometry, and delivery form

3. Reference Flow

Field	Value
What	Production and delivery of a semi-manufactured base-metal or silver product with a mechanically or metallurgically affixed gold layer
How much	1 kg net mass of conforming product at the factory gate
How well	Conforms to the declared substrate specification, gold purity or alloy, gold-layer location and thickness, dimensions, bond-integrity criterion, surface finish, and acceptance test
How long or cycle	One production batch delivered at the factory gate; no service life is assigned because the product is an intermediate material
reference_flow_link	cddd034b-762c-49e3-af56-109b23cfc982

Field	Value
Reference amount	1 kg net conforming product
Reference product flow	Base metals or silver, clad with gold, not further worked than semi-manufactured cddd034b-762c-49e3-af56-109b23cfc982
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	substrate metal and alloy; gold purity or alloy; gold mass and mass fraction; clad faces and layer thickness; product form and dimensions; bonding route; heat-treatment state; surface finish; bond-integrity and dimensional acceptance criteria; recycled content by metal; production site and geography; reporting period; factory-gate delivery form

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

4. Measurement and Unit Rules

rule_id	Applies to	Required property	Required unit	Rule
reference_net_mass	reference product	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg	Measure accepted product after removing packaging, reel, pallet, and other tare; normalize all inventory exchanges to 1 kg net conforming output.
metal_input_mass	copper substrate, gold strip, and gold-clad scrap	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg	Record metal masses on the same dry mass basis; separately report gold mass and substrate-metal mass so composition and metal balance can be checked.
gas_volume_basis	gaseous natural gas and industrial oxygen	Volume 93a60a56-a3c8-22da-a746-0800200c9a66	m3	Report the metered volume and the temperature, pressure, and dry/wet reference conditions; convert only with a documented factor.
electricity_energy_basis	alternating current	Net calorific value 93a60a56-a3c8-11da-a746-0800200c9a66	MJ	Preserve the meter reading and conversion factor when electricity is collected in kWh; use 3.6 MJ per kWh only as an exact unit conversion, not as an energy-performance estimate.

5. System Boundary

rule_id	Applies to	Rule	source_ids
sb_foreground_gate	foreground system boundary	Include all on-site operations from receipt of substrate metal and gold cladding stock through surface preparation, cladding or roll bonding, thermal treatment when used, finish rolling, surface finishing, slitting, inspection, internal handling, and release of the semi-manufactured product at the factory gate.	nist-clad-metals-1983
sb_cladding_identity	product identity	Include only products whose gold covering is affixed by soldering, brazing, welding, hot rolling, or similar mechanical means, including qualifying inlay; exclude plated or coated products that do not meet this definition.	eu-cn-2020-1577-ch71
sb_upstream_inputs	purchased inputs	Link representative upstream datasets for every purchased metal, chemical, fuel, electricity, oxygen, water, and lubricant crossing the foreground boundary; do not include those upstream emissions again as direct foreground elementary flows.	eu-pef-2021-2279
sb_direct_releases	direct site outputs	Record each direct waste and elementary release separately at the point it leaves the foreground process; do not combine scrap, used oil, wastewater, or air emissions into umbrella rows.	eu-pef-2021-2279
sb_downstream_exclusion	downstream life cycle	Exclude downstream conversion into jewellery or components, product use, maintenance, and end-of-life unless the study explicitly expands the boundary and reports those stages separately.	eu-pef-2021-2279

Boundary Abstraction

Field	Value
declared_starting_condition	Purchased copper strip and gold strip are the representative starting materials; the actual substrate metal, alloy, surface condition, dimensions, gold purity, gold form, recycled content, supplier geography, and delivery state must be declared.
starting_condition_role	Defines the first foreground transformation and prevents upstream mining, refining, alloying, or strip production from being silently treated as on-site cladding operations.
product_classification_scope	Base metals or silver clad with gold, not further worked than semi-manufactured; CPC 3.0 code 41340 is mapping context rather than canonical PCR identity.
recursive_input_rule	If an input is already a product within this same gold-clad category, record it once as a separately identified purchased product input with its own upstream dataset and declared starting condition; do not recursively recreate its cladding inventory inside the foreground process.
upstream_dataset_requirement	Every purchased input requires a geographically, technologically, temporally, and materially representative upstream dataset or an explicit documented data gap.
disclosure	Disclose substrate and gold specifications, bonding route, heat source, cleaning and lubricant systems, production and waste-treatment geography, reporting period, allocation choices, data gaps, and any operations performed off site.

6. Process Inventory Structure

Process Map

process_id	process_name	inclusion	inclusion_condition	role	quantitative_reference
gold_cladding_and_finishing	Surface preparation, gold cladding, and semi-finishing	required	Always required; route-specific exchanges are recorded only when the declared technology uses them.	Foreground production from purchased substrate and gold stock to inspected semi-manufactured gold-clad product	1 kg net conforming product output

The cards below describe a representative copper-strip roll-bonding route. If the declared product uses silver or another base-metal substrate, or uses another qualifying cladding technology, replace or add the actual substrate and route-specific exchanges as separate atomic rows; never rename a row as a material or utility collection.

Process: Surface preparation, gold cladding, and semi-finishing (gold_cladding_and_finishing)

Inputs

Product flows

Copper substrate strip (in_copper_strip)

Uncoated copper strip is the representative substrate entering surface preparation. A non-copper product must use a new atomic row naming the actual substrate metal or alloy.

• Selected flow: Red copper strip and sheet
• Flow property / unit: Mass / kg
• Amount rule: measured dry mass accepted into the batch, net of packaging and unrecoverable supplier tare
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_batch_metal_balance
• Sources: nist-clad-metals-1983

Gold cladding strip (in_gold_strip)

Wrought gold strip entering the bond stack is recorded separately from the substrate. Its purity or alloy, thickness, width, and recycled content are required foreground qualifiers.

• Selected flow: Gold strip, semi-manufactured
• Flow property / unit: Mass / kg
• Amount rule: measured dry mass issued to the batch, corrected for returned unused strip
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_batch_metal_balance
• Sources: eu-cn-2020-1577-ch71; nist-clad-metals-1983

Alternating current (in_alternating_current)

Electricity consumed by cleaning equipment, rolling mills, pumps, ventilation, inspection, and other directly attributable foreground equipment is metered or allocated from a reconciled submeter.

• Selected flow: Alternating current
• Flow property / unit: Net calorific value / MJ
• Amount rule: metered electricity attributable to the batch, converted from kWh with the documented exact unit conversion
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_energy_meters
• Sources:

Gaseous natural gas for thermal treatment (in_natural_gas)

Record natural gas only when a directly fired preheating, annealing, or stress-relief operation is inside the foreground boundary.

• Selected flow: natural gas in the gaseous state 4f19ca0e-7b3b-11dd-ad8b-0800200c9a66
• Flow property / unit: Volume / m3
• Amount rule: metered gaseous natural-gas volume attributable to included thermal treatment, with reference conditions retained
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_energy_meters
• Sources: nist-clad-metals-1983

Industrial oxygen for oxygen-assisted heating (in_industrial_oxygen)

Record oxygen only when the declared direct-heating technology supplies industrial oxygen separately to the burner or furnace.

• Selected flow: Industrial oxygen bd4b0f96-2090-4806-a648-335ab20ff401
• Flow property / unit: Volume / m3
• Amount rule: metered oxygen volume attributable to the included oxygen-assisted heating operation, with purity and reference conditions retained
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_energy_meters
• Sources:

Process water for aqueous surface cleaning (in_process_water)

Record water only when aqueous cleaning or rinsing is used before bonding or after finishing; report separately from closed-loop recirculation that does not cross the boundary.

• Selected flow: Process Water 94a04f7e-2d5c-41f0-b182-d54a3b373a02
• Flow property / unit: Mass / kg
• Amount rule: make-up and once-through process-water mass crossing the foreground boundary, excluding internally recirculated volume
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_cleaning_records
• Sources:

Sodium hydroxide for alkaline cleaning (in_sodium_hydroxide)

Record sodium hydroxide only when an alkaline surface-cleaning bath is used. Report pure NaOH equivalent and retain the supplied solution concentration.

• Selected flow: Sodium hydroxide e0abcced-0611-4c24-9290-5a2c5a0c4169
• Flow property / unit: Mass / kg
• Amount rule: purchased or prepared sodium-hydroxide mass charged to the included cleaning operation, expressed as pure NaOH equivalent
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Calculated from collection (calculated_from_collection)
• Collection protocol: cp_cleaning_records
• Sources:

Rolling lubricating oil (in_rolling_lubricant)

Record fresh rolling lubricant only when it is consumed or lost from the foreground lubricant circuit; internally recirculated inventory is not counted again.

• Selected flow: Rolling lubricating oil
• Flow property / unit: Mass / kg
• Amount rule: fresh lubricant make-up plus batch-attributable lubricant loss, net of recovered oil returned to the same circuit
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_lubricant_records
• Sources:

Waste flows

Elementary flows

Outputs

Product flows

Conforming gold-clad semi-manufactured product (out_reference_product)

Accepted product is the quantitative reference. Rejected material and packaging are excluded from its net mass.

• Selected flow: Base metals or silver, clad with gold, not further worked than semi-manufactured cddd034b-762c-49e3-af56-109b23cfc982
• Flow property / unit: Mass / kg
• Amount rule: measured net mass of product passing the declared dimensional, bond-integrity, composition, and surface-finish acceptance criteria
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: 1 kg net conforming product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_batch_metal_balance
• Sources: un-cpc-3-0-2025; eu-cn-2020-1577-ch71

Waste flows

Segregated gold-clad trim scrap (out_gold_clad_scrap)

Record edge trim, offcuts, and rejected clad pieces as this waste only when they retain a gold layer and leave the foreground process for recovery or treatment.

• Selected flow: Waste and scrap of metal clad with gold
• Flow property / unit: Mass / kg
• Amount rule: measured dry mass of segregated gold-clad trim, offcuts, and rejected pieces leaving the foreground boundary
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_batch_metal_balance
• Sources: nist-clad-metals-1983

Used lubricating oil (out_used_lubricating_oil)

Spent rolling lubricant removed from the circuit and transferred for recovery, treatment, or disposal is recorded separately from fresh make-up oil.

• Selected flow: Used lubricating oil 55d93375-7f04-4166-b2a2-88ce929051a5
• Flow property / unit: Mass / kg
• Amount rule: measured mass of used lubricating oil leaving the foreground boundary, net of free water when separately measured
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_lubricant_records
• Sources:

Wastewater from cleaning (out_cleaning_wastewater)

Record aqueous cleaning and rinse wastewater when it leaves the cladding process for on-site treatment, off-site treatment, or documented discharge. Retain alkalinity, dissolved-metal concentrations, and destination as qualifiers.

• Selected flow: Wastewater from cleaning f0402393-e82c-47e8-9cd8-a486c97f3e89
• Flow property / unit: Mass / kg
• Amount rule: measured wastewater mass leaving the foreground process, with separately added water and removed bath inventory reconciled
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_cleaning_records
• Sources:

Elementary flows

Direct fossil carbon dioxide from on-site fuel combustion (out_fossil_carbon_dioxide)

Record only carbon dioxide directly released by foreground combustion of fossil fuel. Electricity-related or other upstream carbon dioxide remains in linked upstream datasets.

• Selected flow: carbon dioxide (fossil) 08a91e70-3ddc-11dd-923d-0050c2490048
• Flow property / unit: Mass / kg
• Amount rule: site-measured or site-calculated direct fossil carbon-dioxide mass attributable to included combustion, using documented fuel carbon and oxidation data
• Value mode: Calculated value (calculated_value)
• Specificity: Site-specific (site_specific)
• Normalization basis: per 1 kg net conforming gold-clad product
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Calculated from collection (calculated_from_collection)
• Collection protocol: cp_direct_emissions
• Sources:

7. Allocation and Co-product Handling

rule_id	Applies to	Rule	source_ids
alloc_subdivide_first	shared foreground operations	Avoid allocation by submetering or subdividing cleaning, rolling, thermal treatment, finishing, and waste handling whenever inputs and releases can be directly assigned to the declared gold-clad product.	eu-pef-2021-2279
alloc_physical_second	unavoidable multifunctionality	When subdivision or system expansion is not feasible, use a documented causal physical relationship relevant to the shared operation; do not default to total mass when gold-clad and other outputs cause materially different burdens.	eu-pef-2021-2279
alloc_economic_last	residual shared burdens	Use economic allocation only when no defensible physical relationship exists; use contemporaneous factory-gate values for all co-products, disclose price sources and averaging period, and test sensitivity because gold content can dominate value.	eu-pef-2021-2279
alloc_scrap_status	gold-clad trim and used materials	Classify each outgoing material as waste or co-product according to its actual control, destination, and market status. Do not assign an avoided-burden credit inside this factory-gate PCR unless an explicitly expanded system and substitution evidence are reported.	eu-pef-2021-2279

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_batch_metal_balance	gold_cladding_and_finishing	copper substrate, gold strip, accepted product, and gold-clad scrap	weighbridge, calibrated scale, material issue, return, and acceptance records	batch_id; material_id; alloy_or_purity; gross_mass; tare_mass; returned_mass; accepted_mass; scrap_mass; gold_layer_spec; calibration_id	Reconcile supplier receipt, batch issue/return, product acceptance, and segregated scrap records on one dry mass basis.	kg	each batch	all batches in the reporting period	all included lines at the declared site	Sum net input and output masses by batch, then divide reporting-period totals by net accepted product mass.	scale calibration; material certificates; batch traveller; acceptance and scrap tickets
cp_energy_meters	gold_cladding_and_finishing	alternating current, natural gas, and industrial oxygen	utility meter, submeter, invoice, and production log	meter_id; opening_reading; closing_reading; unit; reference_conditions; batch_or_period; downtime; shared_load_basis	Prefer dedicated meters; otherwise reconcile site totals and allocate only the directly attributable share using documented operating data.	MJ for electricity; m3 for gases	meter interval and each production campaign	representative reporting period of at least 12 months or the full shorter campaign	all included foreground equipment	Subtract non-production and excluded loads, reconcile to invoices, and normalize attributable totals by accepted product mass.	meter calibration; invoice reconciliation; operating-hour and production logs
cp_cleaning_records	gold_cladding_and_finishing	process water, sodium hydroxide, and cleaning wastewater	tank batch sheet, chemical issue, water meter, concentration test, and effluent record	bath_id; water_makeup; NaOH_solution_mass; NaOH_concentration; rinse_water; wastewater_mass; pH; dissolved_metals; destination	Record every bath make-up, replenishment, dump, and rinse; calculate pure NaOH equivalent from solution mass and measured concentration.	kg	each bath event and meter interval	all cleaning events in the reporting period	all included cleaning and rinse stations	Reconcile water and bath inventories, aggregate by period, and normalize by accepted product mass.	meter calibration; concentration analysis; pH and dissolved-metal results; waste transfer or discharge record
cp_lubricant_records	gold_cladding_and_finishing	fresh rolling oil and used lubricating oil	stores issue, tank inventory, recovery return, and waste transfer record	lubricant_id; formulation; opening_stock; additions; recovered_return; closing_stock; used_oil_mass; free_water; destination	Perform a lubricant stock balance and separately weigh used oil leaving the site.	kg	each addition/removal and monthly stock close	all lubricant events in the reporting period	included rolling and finishing mills	Fresh consumption equals opening stock plus additions minus closing stock and separately recovered return; normalize fresh and used outputs independently.	tank calibration; purchase issue; recovery and waste transfer records
cp_direct_emissions	gold_cladding_and_finishing	direct fossil carbon dioxide	fuel meter, fuel composition certificate, stack measurement, or approved site mass-balance record	fuel_volume_or_mass; reference_conditions; carbon_content; fossil_fraction; oxidation_fraction; measured_CO2; method_id	Prefer representative stack measurement; otherwise calculate from collected fuel and supplier-specific carbon data with the equation and factors retained.	kg CO2	each test campaign or reporting-period calculation	representative operating modes over the reporting period	all included direct combustion units	Aggregate only direct fossil CO2 from included equipment and normalize by accepted product mass.	laboratory or analyser QA; fuel certificate; meter calibration; calculation review

Calculation Rules

rule_id	Applies to	Formula or rule	Inputs	Output	source_ids
calc_net_reference_mass	accepted product	Net reference-product mass = accepted gross mass - packaging, reel, pallet, and other measured tare.	accepted gross mass; tare mass	out_reference_product net kg
calc_pure_naoh	sodium hydroxide input	Pure NaOH equivalent = solution mass × measured NaOH mass fraction; retain both raw values.	NaOH solution mass; measured concentration	in_sodium_hydroxide kg pure NaOH
calc_inventory_normalization	every inventory row	Normalized amount = reporting-period attributable amount ÷ reporting-period net conforming product mass.	attributable row amount; net conforming product mass	row amount per 1 kg reference product	eu-pef-2021-2279
calc_metal_balance	substrate, gold, product, and metal-bearing outputs	Reconcile separately measured substrate-metal and gold inputs against their masses in accepted product, segregated scrap, wastewater, and any additional separately named metal-bearing output; report closure and unresolved difference without forcing balance.	metal input masses; product composition; scrap composition; wastewater metal analyses; other named metal outputs	substrate-metal and gold mass-balance closure
calc_direct_fossil_co2	direct fossil carbon dioxide	Use representative measured CO2, or calculate fossil CO2 from collected fuel quantity, carbon content, fossil fraction, and oxidation fraction; retain the site equation and all factors.	collected fuel; carbon content; fossil fraction; oxidation fraction or stack measurement	out_fossil_carbon_dioxide kg

Data Quality Requirements

requirement_id	Applies to	Requirement	Evidence
dq_product_identity	reference product and metal inputs	Retain purchase and product specifications that identify substrate alloy, gold purity or alloy, layer location and thickness, product form, dimensions, bond route, and delivery state.	supplier certificate; internal specification; batch traveller; inspection report
dq_mass_completeness	metal mass balance	Cover every batch in the reporting period and reconcile copper or actual substrate metal and gold separately; explain each unclosed difference and excluded metal-bearing stream.	calibrated scale records; material issue and return records; product and scrap composition tests
dq_temporal_representativeness	all foreground exchanges	Use a continuous representative period that captures normal product mix, start-up, shutdown, maintenance, and route variation; justify any period shorter than 12 months.	production calendar; meter coverage; downtime and maintenance logs
dq_technology_geography	foreground site and upstream links	Declare site, country or grid region, bonding technology, heat source, cleaning system, lubricant system, and waste destinations; select upstream datasets matching these facts or disclose mismatch.	site metadata; process flow diagram; supplier and utility records; dataset representativeness review
dq_measurement_quality	meters, scales, analyses, and calculations	Retain calibration status, detection limits where relevant, sampling plans, conversion factors, estimation flags, and calculation review for each material exchange.	calibration certificates; laboratory QA/QC; calculation workbook or reproducible record
dq_primary_data_priority	most relevant foreground processes	Use site-specific primary data for the cladding and finishing process and for major metal, energy, water, waste, and direct-emission exchanges; document any proxy and its expected influence.	primary-data register and data-quality assessment consistent with eu-pef-2021-2279

9. Validation Rules

rule_id	Applies to	Rule	source_ids
val_identity_boundary	product classification	Confirm the output has a base-metal or silver substrate and a gold covering affixed by a qualifying mechanical or metallurgical cladding means, remains semi-manufactured, and is not merely plated or coated.	un-cpc-3-0-2025; eu-cn-2020-1577-ch71
val_reference_flow	quantitative reference	Confirm the reference amount is exactly 1 kg net conforming product and every required qualifier is populated.
val_atomic_inventory	inventory structure	Confirm every selected flow is one atomic product, waste, or elementary exchange; reject collection labels, combined utilities, combined wastes, and unnamed route alternatives.
val_uuid_identity	Tiangong references	Confirm every populated UUID resolves at public state code 100 with matching English and Chinese names, flow type, classification, property, and unit group; keep unresolved rows empty and documented.
val_mass_balance	copper or actual substrate metal and gold	Check separate substrate-metal and gold closures using inputs, accepted product composition, segregated scrap, wastewater analyses, and every additional named metal-bearing output; investigate rather than erase differences.
val_energy_emissions	energy and direct emissions	Reconcile electricity, fuel, and oxygen records to included equipment and reporting period; ensure direct fossil CO2 excludes upstream electricity and fuel-supply emissions.
val_allocation	multifunctional operations	Confirm subdivision was attempted first and every residual physical or economic allocation basis, dataset, period, and sensitivity is disclosed.	eu-pef-2021-2279
val_bilingual_alignment	bilingual PCR use	Confirm English and Chinese files contain the same process ids, row ids, controlled values, rule ids, UUIDs, and source ids.

10. Published Dataset Profile

Field	Value
dataset_role	Foreground production dataset for factory-gate semi-manufactured gold-clad base metal or silver
downstream_use	secondary_dataset; background_dataset
allowed_use	Product-level or component-level LCA in which the declared substrate, gold layer, product form, route, site, geography, reporting period, and factory-gate boundary are representative
excluded_use	Gold electroplating or other non-clad coatings; solid gold products; finished jewellery or components without added downstream processes; undisclosed substrate or gold layer; attribution to a different route or geography without representativeness review
required_metadata	canonical PCR id; product UUID; substrate and gold specifications; product form and dimensions; bonding and heat-treatment route; site and geography; reporting period; reference flow; upstream dataset choices; allocation method; recycled content; waste destinations
required_quality_disclosure	primary-data coverage; meter and scale calibration; gold and substrate-metal balance closure; data gaps and proxies; temporal, technological, and geographic representativeness; uncertainty and allocation sensitivity
update_trigger	Change in substrate or gold specification, cladding or heat-treatment technology, product form, site, energy system, cleaning or lubricant system, waste route, allocation basis, upstream dataset representativeness, or a material shift in measured inventory

11. Data Sources

Source id	Type	Reference	Used for
un-cpc-3-0-2025	Official guidance (official_guidance)	United Nations Statistics Division, CPC Version 3.0 Structure, 30 June 2025, code 41340. https://unstats.un.org/unsd/classifications/Econ/Download/In%20Text/CPC_Ver_3.0_Structure_30Jun2025.csv (retrieved 2026-09-04)	Official product classification identity and title
eu-cn-2020-1577-ch71	Official guidance (official_guidance)	European Commission, Commission Implementing Regulation (EU) 2020/1577, Combined Nomenclature 2021, Chapter 71 notes 6-7 and heading 7109. https://eur-lex.europa.eu/eli/reg_impl/2020/1577/oj/eng/pdf (retrieved 2026-09-04)	Original-text definition of metal clad with precious metal, distinction from plating, and category boundary
nist-clad-metals-1983	Literature (literature)	J. T. Skelly, “Clad Metals - Material Conservation Through Design for Corrosion Control and High Performance,” in Technical Aspects of Critical Materials Use by the Steel Industry, Volume I, NBSIR 83-2679-1, 1983, pp. P39-1 to P39-2. https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nbsir83-2679-1.pdf (retrieved 2026-09-04)	Original-text process decomposition for cleaning, continuous cold roll bonding, thermal treatment, finish rolling, annealing, polishing, and slitting; distinction between clad and plated metal
eu-pef-2021-2279	Official guidance (official_guidance)	European Commission, Recommendation (EU) 2021/2279, Annex I, Environmental Footprint methods, especially sections 4.5 and data-quality provisions. https://eur-lex.europa.eu/eli/reco/2021/2279/2021-12-30/eng (retrieved 2026-09-04)	System-boundary disclosure, allocation hierarchy, foreground data quality, and representativeness rules