Ball or roller bearings

1. Scope and Applicability

This PCR applies to complete ball or roller bearings supplied as finished products. It covers radial and thrust configurations and conventional bearing variants that use balls or rollers between raceways, with cages, seals, shields, lubricant, or preservation treatment when those features are part of the sold bearing. It supports a cradle-to-factory-gate foreground data package normalized to net bearing mass.

Loose bearing parts, balls or rollers sold separately, bearing housings and plain shaft bearings, gears and gearboxes, ball or roller screws, magnetic bearings, fluid-film bearings, maintenance services, remanufacturing services, and use-phase performance are outside this PCR. A bearing unit is included only when its sold product is classified and reported as a complete ball or roller bearing; otherwise use the PCR for its actual product category. The CPC identity is supported by un-cpc-3-0-structure-2025, and the category boundary is consistent with international-epd-pcr-2023-03.

2. Product Category Identity

Field	Value
canonical_pcr_id	pcr.metal-products-machinery-and-equipment.general-purpose-machinery.ball-or-roller-bearings
classification_refs	CPC 3.0: 43310, Ball or roller bearings (un-cpc-3-0-structure-2025)
covered_products	Complete finished bearings in which balls or rollers roll between bearing raceways; radial or thrust types; open, shielded, or sealed variants; lubricated or preservative-coated variants when sold in that state
excluded_products	Loose parts and rolling elements; bearing housings and plain bearings; gears, gearboxes, screws, couplings, and drives; magnetic or fluid-film bearings; services; downstream application equipment
representative_product	A finished, inspected ball or roller bearing with declared type, dimensions, mass, material specification, accuracy, internal clearance, load rating, sealing, and lubrication state
production_route	Forming and turning; heat treatment; grinding and honing or superfinishing; cleaning; assembly; lubrication or preservation as applicable; inspection; packaging, with outsourced steps represented by specific upstream datasets
market_state	Conforming finished bearing at the manufacturer factory gate, preserved and packaged as sold; packaging mass is reported separately from net bearing mass

3. Reference Flow

Field	Value
What	Finished ball or roller bearings at the manufacturer factory gate
How much	1 kg net mass of conforming bearing product, excluding separately reported packaging
How well	Meets the declared product specification and has passed applicable dimensional, internal-clearance, surface, visual, free-running, vibration or noise, and marking inspections
How long or cycle	Factory-gate declared unit; no service-life cycle is represented. If a downstream study models use, it must separately declare application, load, speed, lubrication, environment, maintenance, and service-life assumptions.
reference_flow_link	The output row final_bearing_output is the reference flow and is normalized to exactly 1 kg.

Field	Value
Reference amount	1 kg
Reference product flow	Ball or roller bearings 9b10184f-db9d-4cc7-94b5-02ab19ca370d
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	manufacturer and site geography; reporting period; product designation; ball or roller type and subtype; radial or thrust arrangement; bore, outside diameter, and width; net bearing mass; ring and rolling-element material grades; cage material and presence; seal or shield state; lubricant type and fill; preservation state; accuracy and internal-clearance classes; basic load ratings or declared performance specification; integrated and outsourced manufacturing steps; allocation method; packaging composition and mass

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
measurement_reference_mass	Reference product and all mass-normalized exchanges	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg	Weigh or calculate net conforming bearing mass after final inspection and before adding separately reported packaging. Normalize every inventory exchange to 1 kg net bearing output.
measurement_electricity	Electricity rows	Net calorific value 93a60a56-a3c8-11da-a746-0800200c9a66	MJ	Preserve the Tiangong energy property. Convert measured kWh to MJ by multiplying by 3.6 and retain the original meter records, meter boundary, and electricity supply mix.
measurement_gas_volume	Gaseous natural gas	Volume 93a60a56-a3c8-22da-a746-0800200c9a66	m3	Report metered volume at declared reference temperature and pressure. If records use mass or energy, use supplier- or meter-specific conversion data and disclose the conversion basis; do not apply an undocumented generic factor.
measurement_water_mass	Process water and cleaning wastewater	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg	Prefer direct mass records. When meters report volume, convert using measured or documented site-specific density and preserve volume, density, temperature, and conversion records.
measurement_material_balance	Steel input, bearing output, steel chips, and steel swarf	Mass 93a60a56-a3c8-11da-a746-0800200b9a66	kg	Reconcile received steel, work in progress, conforming output, rejects, chips, swarf, and stock change over the reporting period. Record oil, water, and abrasive retained in waste separately or disclose their inclusion in measured waste mass.

5. System Boundary

The foreground boundary begins when steel, purchased parts, auxiliaries, energy, water, and packaging are received at the reporting manufacturing site or at a contracted operation attributed to the product. It ends with the conforming, preserved, inspected, and packaged bearing leaving the factory gate. The operation sequence and inspection stages follow the bearing-manufacturing descriptions in skf-insert-bearings-18033; material, auxiliary, energy, cleaning, packaging, and residual-product relevance follows skf-green-bearings.

Boundary Abstraction

Field	Value
declared_starting_condition	Delivered bearing-grade steel and any purchased bearing parts, auxiliaries, energy, process water, and packaging at the reporting site gate, with supplier, material grade, product state, recycled content when known, and upstream dataset identified
starting_condition_role	Foreground manufacturing input; extraction and production of purchased goods and energy are represented by linked upstream datasets rather than repeated inside the foreground process
product_classification_scope	Complete ball or roller bearings; loose parts and other power-transmission products remain outside the reference-product identity
recursive_input_rule	A purchased complete ball or roller bearing used as a component must be recorded once as an upstream product input with its own dataset and must not be recursively decomposed under this PCR unless the study intentionally replaces that supplier dataset with primary component records
upstream_dataset_requirement	Use supplier-specific datasets where available for bearing steel, purchased components, lubricant, preservation oil, packaging, electricity, natural gas, and water; otherwise use geographically, technologically, temporally, and materially representative datasets and disclose substitutions
disclosure	Declare which operations are on-site or outsourced, the incoming state of steel and parts, furnace and finishing technologies, cleaning route, lubrication and preservation state, rejects and rework, waste destinations, packaging, site geography, reporting period, and exclusions

System Boundary Rules

rule_id	Applies to	Rule	source_ids
boundary_rule_1	foreground_operations	Include forming and turning, heat treatment, grinding and honing or superfinishing, cleaning, assembly, lubrication or sealing when applicable, inspection, preservation, and packaging when they are performed under the producer's control or attributed contract manufacturing.	skf-insert-bearings-18033; skf-green-bearings
boundary_rule_2	purchased_inputs	Link cradle-to-gate upstream datasets for every purchased material, component, auxiliary, energy carrier, water supply, and packaging input; do not treat the reporting-site gate as a zero-burden origin.	skf-green-bearings; eu-recommendation-2021-2279
boundary_rule_3	outsourced_steps	Represent an outsourced manufacturing step once, either as a supplier-specific process or within a purchased-component dataset. Do not also count the same energy, auxiliary, waste, or emission in the reporting-site inventory.	skf-insert-bearings-18033
boundary_rule_4	downstream_stages	Exclude distribution after the factory gate, mounting, operation, maintenance, replacement, remanufacturing, and end of life from this declared unit. A downstream model may add them only with separately declared application and scenario data.	international-epd-pcr-2023-03
boundary_rule_5	capital_goods_and_minor_flows	Do not apply an automatic mass or cost cut-off. Include measured production exchanges and disclose any excluded capital good or minor flow with a documented significance check for the intended study.	eu-recommendation-2021-2279

6. Process Inventory Structure

Process Map

process_id	process_name	inclusion	inclusion_condition	role	quantitative_reference
forming_and_turning	Component forming and turning	required	Model on-site records when rings or rolling elements are formed or turned by the reporting producer; otherwise link the supplier-specific component process and record no duplicate on-site burden.	Foreground material conversion and machining	Per 1 kg conforming finished bearing output
heat_treatment	Heat treatment	required	Model the actual electric, gas-fired, or outsourced route; the natural-gas and direct-combustion rows apply only to gas-fired equipment within the foreground boundary.	Foreground hardening and stabilization	Per 1 kg conforming finished bearing output
grinding_honing_cleaning	Grinding, honing, superfinishing, and cleaning	required	Model actual wet or dry finishing and aqueous or non-aqueous cleaning; the water and wastewater rows apply only when process water crosses the boundary.	Foreground precision finishing and cleaning	Per 1 kg conforming finished bearing output
assembly_lubrication_preservation	Assembly, lubrication, sealing, and preservation	required	Grease and preservation-oil rows apply only when those products are added within the foreground boundary; declare open, shielded, or sealed product state.	Foreground final assembly and protection	Per 1 kg conforming finished bearing output
inspection_packaging	Final inspection and packaging	required	Model the inspections required by the declared product specification and each packaging component actually used; the corrugated-box row applies only when used.	Foreground conformity release and factory-gate output	Per 1 kg conforming finished bearing output

Process: Component forming and turning (forming_and_turning)

Inputs

Product flows

Bearing-grade high-carbon chromium steel input (bearing_steel_input)

Record the mass of bearing-grade steel bar, tube, wire, forging, or other declared feedstock entering producer-controlled forming and turning. Keep alloy grade, metallurgical state, product form, supplier, recycled content when known, and upstream dataset with the foreground record.

• Selected flow: Bearing-grade high-carbon chromium steel
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured received mass less documented returns and reporting-period stock increase, attributed to conforming output
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_material_mass
• Sources: skf-green-bearings

Electricity for forming and turning (forming_electricity)

Record purchased or self-generated electricity delivered to forging, cold forming, turning, material handling, and directly attributable support equipment for this stage.

• Selected flow: Electricity 890a70b7-b677-4e2a-8a1b-7d017e0a10ae
• Flow property / unit: Net calorific value 93a60a56-a3c8-11da-a746-0800200b9a66 / MJ 93a60a57-a3c8-11da-a746-0800200c9a66
• Amount rule: measured stage electricity converted to MJ and attributed to conforming output
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_stage_electricity
• Sources: skf-green-bearings

Waste flows

No default waste input crosses this process boundary.

Elementary flows

No default elementary input is prescribed.

Outputs

Product flows

Internal work-in-progress transfers are not external inventory exchanges; preserve them in the site mass balance and do not double count them as purchased products.

Waste flows

Steel machining chips from turning (steel_machining_chips)

Record segregated ferrous chips generated by turning and other chip-forming operations. Declare alloy grade, cutting-fluid contamination, on-site recovery, and destination.

• Selected flow: Steel machining chips 69609b56-5e59-4f7d-9847-2eae3ea031b7
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured wet or dry chip mass, with measurement state declared, leaving the process for internal recovery or external treatment
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_waste_mass
• Sources: skf-green-bearings

Elementary flows

Record any measured direct dust or other elementary emission as a separate species-specific row in the foreground data package; no category-generic default is imposed here.

Process: Heat treatment (heat_treatment)

Inputs

Product flows

Electricity for heat treatment (heat_treatment_electricity)

Record electricity supplied to furnaces, quench circulation, washing, controls, and directly attributable heat-treatment support equipment.

• Selected flow: Electricity 890a70b7-b677-4e2a-8a1b-7d017e0a10ae
• Flow property / unit: Net calorific value 93a60a56-a3c8-11da-a746-0800200b9a66 / MJ 93a60a57-a3c8-11da-a746-0800200c9a66
• Amount rule: measured heat-treatment electricity converted to MJ and attributed to conforming output
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_stage_electricity
• Sources: skf-insert-bearings-18033

Gaseous natural gas for heat treatment (natural_gas_heat_treatment)

Record natural gas only when it is combusted in producer-controlled heat-treatment or directly attributable thermal equipment. Declare reference conditions, supplier, composition or calorific-value record, and furnace technology.

• Selected flow: natural gas in the gaseous state 4f19ca0e-7b3b-11dd-ad8b-0800200c9a66
• Flow property / unit: Volume 93a60a56-a3c8-22da-a746-0800200c9a66 / m3 93a60a57-a3c8-12da-a746-0800200c9a66
• Amount rule: metered gas volume at declared reference conditions; record zero and not-applicable evidence for a fully electric or outsourced route
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_natural_gas
• Sources: skf-insert-bearings-18033

Waste flows

No default waste input crosses this process boundary. Spent quench oil, salt, or bath media must be added as separate chemically specific rows when used.

Elementary flows

No default elementary input is prescribed.

Outputs

Product flows

Internal heat-treated work in progress is tracked in production records and is not duplicated as an external product flow.

Waste flows

Add each spent quench medium, furnace residue, or rejected heat-treated component as a separate concrete waste row when applicable.

Elementary flows

Direct fossil carbon dioxide from natural-gas combustion (fossil_co2_heat_treatment)

Record only direct fossil carbon dioxide crossing to air from natural gas combusted within the foreground boundary. Do not copy upstream electricity or fuel-supply emissions into this row.

• Selected flow: carbon dioxide (fossil) 08a91e70-3ddc-11dd-923d-0050c2490048
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured stack mass or calculated fossil CO2 from metered fuel and supplier-specific carbon content according to calc_direct_fossil_co2
• Value mode: Calculated value (calculated_value)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Calculated from collection (calculated_from_collection)
• Collection protocol: cp_direct_combustion
• Sources: skf-green-bearings

Process: Grinding, honing, superfinishing, and cleaning (grinding_honing_cleaning)

Inputs

Product flows

Electricity for grinding, honing, superfinishing, and cleaning (grinding_electricity)

Record electricity for grinding, honing or superfinishing, coolant circulation, aqueous cleaning, filtration, and directly attributable support equipment.

• Selected flow: Electricity 890a70b7-b677-4e2a-8a1b-7d017e0a10ae
• Flow property / unit: Net calorific value 93a60a56-a3c8-11da-a746-0800200b9a66 / MJ 93a60a57-a3c8-11da-a746-0800200c9a66
• Amount rule: measured stage electricity converted to MJ and attributed to conforming output
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_stage_electricity
• Sources: skf-insert-bearings-18033; skf-green-bearings

Process water for aqueous cleaning (process_water_cleaning)

Record process water delivered to aqueous cleaning only when this route is operated within the foreground boundary. Declare water source, quality, recirculation, make-up versus total circulation, and delivery boundary.

• Selected flow: Process Water 94a04f7e-2d5c-41f0-b182-d54a3b373a02
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured make-up water crossing the site or process boundary; do not report recirculated water repeatedly
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_process_water
• Sources: skf-green-bearings

Waste flows

No default waste input crosses this process boundary.

Elementary flows

No default elementary input is prescribed.

Outputs

Product flows

Internal finished components are tracked in production records and are not duplicated as external product flows.

Waste flows

Steel swarf from grinding (steel_grinding_swarf)

Record fine steel swarf removed during grinding, honing, or superfinishing. Declare whether the measured mass includes grinding fluid, abrasive, water, or filter media and record its treatment destination.

• Selected flow: Steel swarf 6a16eab5-8097-4e37-8d28-aa1e81b8bb5c
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured swarf mass in the declared wet or dry state leaving the process for recovery or treatment
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_waste_mass
• Sources: skf-green-bearings

Wastewater from aqueous cleaning (cleaning_wastewater)

Record cleaning wastewater transferred to on-site treatment, sewer, or an external waste handler. Declare cleaning chemistry, contaminant load, internal recycling, treatment boundary, and destination.

• Selected flow: Wastewater from cleaning f0402393-e82c-47e8-9cd8-a486c97f3e89
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured wastewater mass crossing the selected treatment boundary, net of documented internal recirculation
• Value mode: Foreground record (foreground_record)
• Specificity: Technology-specific (technology_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_cleaning_wastewater
• Sources: skf-green-bearings

Elementary flows

Report measured releases from cleaning or finishing as separate substance- and compartment-specific elementary rows; do not use an umbrella emissions row.

Process: Assembly, lubrication, sealing, and preservation (assembly_lubrication_preservation)

Inputs

Product flows

Rolling-bearing lubricating grease (bearing_lubricating_grease)

Record the grease placed in the bearing only for grease-lubricated products. Declare manufacturer and grade, base oil, thickener, consistency or specification, fill mass, and whether the bearing is sealed for life.

• Selected flow: Rolling-bearing lubricating grease
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured grease issued to conforming bearings less documented recoverable return and reporting-period stock increase
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_auxiliary_mass
• Sources: skf-insert-bearings-18033; skf-green-bearings

Bearing rust-preventive oil (bearing_rust_preventive_oil)

Record the rust-preventive oil applied to the finished bearing only when preservation is part of the factory-gate product state. Declare formulation or grade, application method, retained mass, and volatile fraction when relevant.

• Selected flow: Bearing rust-preventive oil
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured oil issued less documented return, with retained and waste fractions reconciled
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming finished bearing output
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_auxiliary_mass
• Sources: skf-insert-bearings-18033; skf-green-bearings

Waste flows

Add each used lubricant, spent preservation bath, rejected seal, cage, ring, or rolling element as a separate concrete waste row when it crosses the selected boundary.

Elementary flows

No default elementary input is prescribed.

Outputs

Product flows

The assembled bearing proceeds to final inspection and packaging as internal work in progress and is not duplicated as an external product flow.

Waste flows

No category-generic assembly waste is prescribed; use actual species- or material-specific records.

Elementary flows

Report measured volatile or other direct releases as separate substance- and compartment-specific rows when applicable.

Process: Final inspection and packaging (inspection_packaging)

Inputs

Product flows

Corrugated board boxes (packaging_corrugated_boxes)

Record corrugated board boxes only when they are used to deliver the reference bearing. Declare box specification, mass, supplier, recycled content when known, and whether additional packaging components are separately recorded.

• Selected flow: corrugated board boxes 4f197bec-7b3b-11dd-ad8b-0800200c9a66
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: measured box mass issued to packaged conforming bearing output
• Value mode: Foreground record (foreground_record)
• Specificity: Product-specific (product_specific)
• Normalization basis: per 1 kg conforming finished bearing output; packaging excluded from net reference-product mass
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_packaging_mass
• Sources: skf-green-bearings

Waste flows

No default waste input crosses this process boundary.

Elementary flows

No default elementary input is prescribed.

Outputs

Product flows

Conforming finished bearing at factory gate (final_bearing_output)

Record only conforming released product after applicable clearance, free-running, vibration or noise, visual, dimensional, marking, preservation, and packaging checks. Packaging mass is not part of the 1 kg net bearing output.

• Selected flow: Ball or roller bearings 9b10184f-db9d-4cc7-94b5-02ab19ca370d
• Flow property / unit: Mass 93a60a56-a3c8-11da-a746-0800200b9a66 / kg 93a60a57-a4c8-11da-a746-0800200c9a66
• Amount rule: exactly 1 kg net conforming bearing output by definition of the reference flow
• Value mode: Fixed value (fixed_value)
• Specificity: Generic (generic)
• Normalization basis: PCR reference flow
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Identity reference (identity_reference)
• Sources:

Waste flows

Record each rejected bearing or rejected component separately by its physical identity and actual treatment route; do not merge rejects with chips or swarf.

Elementary flows

No default direct elementary output is prescribed for inspection and packaging.

7. Allocation and Co-product Handling

rule_id	Applies to	Rule	source_ids
allocation_rule_1	shared_processes	Avoid allocation by subdividing production lines, batches, meters, furnaces, and waste records so inputs and outputs directly attributable to the declared bearing are collected separately.	eu-recommendation-2021-2279
allocation_rule_2	unavoidable_shared_burdens	When subdivision is not possible, use a causal physical relationship such as machine time, furnace occupancy, metered energy, processed mass, surface area, or batch time. Document the driver, numerator, denominator, affected products, and sensitivity.	eu-recommendation-2021-2279
allocation_rule_3	non_physical_allocation	Use economic or another non-physical relationship only after documenting why subdivision and a relevant physical relationship are infeasible. Record prices, period, geography, co-product status, and sensitivity.	eu-recommendation-2021-2279
allocation_rule_4	recycled_metal_and_waste	Keep the burdens of collecting, conditioning, and treating chips, swarf, wastewater, and other wastes on the generating system until the declared treatment or end-of-waste boundary. Report any recycling credit or substitution scenario separately; do not subtract it invisibly from foreground quantities.	eu-recommendation-2021-2279
allocation_rule_5	rework_and_internal_recycling	Track internal rework and recirculated material without creating a second product output. Count only net external inputs and outputs while retaining gross process records for audit and mass-balance checks.	skf-green-bearings

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_material_mass	forming_and_turning	bearing_steel_input	scale and stock records	alloy grade; delivered form; gross and tare mass; opening and closing stock; returns; work in progress	Weigh steel charged by alloy and route and reconcile stock, returns, chips, and work in progress.	kg	each receipt and production batch	representative reporting period	reporting site and attributed contracted forming	net attributable mass divided by conforming output mass	scale identity, calibration status, stock reconciliation, supplier record
cp_stage_electricity	forming_and_turning; heat_treatment; grinding_honing_cleaning	forming_electricity; heat_treatment_electricity; grinding_electricity	electricity meter records	meter reading; timestamp; meter boundary; stage; batch; shared-load driver	Collect separate stage meters; allocate shared meters only with documented machine time, checked rated load, or furnace occupancy.	kWh and MJ	continuous or each batch	same period as output	each included site and outsourced operation	stage total converted to MJ and divided by conforming output mass	meter identity, calibration, allocation worksheet, energy invoice reconciliation
cp_waste_mass	forming_and_turning; grinding_honing_cleaning	steel_machining_chips; steel_grinding_swarf	waste scale and dispatch records	gross mass; tare; wet or dry state; alloy; retained fluid; destination; end-of-waste status	Weigh each stream separately at removal and correct for documented container tare.	kg	each removal	same period as output	each generating operation	net stream mass divided by conforming output mass	weigh ticket, tare record, waste transfer record, moisture or retained-fluid note
cp_natural_gas	heat_treatment	natural_gas_heat_treatment	gas meter or reconciled billing record	volume; temperature; pressure; timestamp; furnace; composition or calorific value	Read the heat-treatment meter or reconcile billed volume to furnace operation and state reference conditions.	m3	continuous or each furnace batch	same period as heat-treated output	gas-fired heat treatment within foreground boundary	attributable reference-condition volume divided by conforming output mass	meter identity, calibration, bill reconciliation, supplier specification
cp_direct_combustion	heat_treatment	fossil_co2_heat_treatment	stack result or fuel-carbon calculation	stack mass or fuel quantity; carbon content or emission factor; oxidation fraction; unit conversion	Prefer site stack or fuel-carbon records; otherwise calculate from metered gas with a documented supplier factor and oxidation assumption.	kg	each monitored period or furnace batch	same period as fuel record	foreground gas-fired equipment only	direct fossil CO2 divided by conforming output mass	stack report or complete factor provenance and calculation sheet
cp_process_water	grinding_honing_cleaning	process_water_cleaning	water meter or scale record	make-up quantity; source; quality; temperature; density; recirculation boundary	Meter or weigh net make-up process water delivered to cleaning; exclude gross recirculating flow.	kg	continuous or each cleaning batch	same period as cleaned output	foreground aqueous-cleaning system	net make-up mass divided by conforming output mass	meter identity, calibration, density conversion, water balance
cp_cleaning_wastewater	grinding_honing_cleaning	cleaning_wastewater	effluent meter, scale, and dispatch record	quantity; temperature; density; destination; contaminant characterization	Meter or weigh wastewater leaving the foreground boundary and reconcile it to water input, retention, and evaporation.	kg	continuous or each discharge	same period as cleaning input	foreground aqueous-cleaning system	boundary-crossing wastewater mass divided by conforming output mass	meter or weigh ticket, density conversion, water balance, treatment record
cp_auxiliary_mass	assembly_lubrication_preservation	bearing_lubricating_grease; bearing_rust_preventive_oil	scale, purchase, and stock records	product name; grade; supplier; lot; gross and tare mass; opening and closing stock	Weigh or reconcile each separately specified auxiliary actually used or retained on the bearing.	kg	each batch and reporting period	same period as assembled output	assembly and preservation operations	net attributable product mass divided by conforming output mass	scale calibration, purchase and stock reconciliation, product specification or safety-data identifier
cp_packaging_mass	inspection_packaging	packaging_corrugated_boxes	packaging scale and issue record	box specification; gross and tare mass; issued, unused, and returned quantities; recycled content	Weigh boxes issued to declared output, net of unused stock and returns, outside net bearing mass.	kg	each packaging batch	same period as packaged output	final packaging operation	box mass divided by net conforming bearing mass	scale calibration, packaging issue reconciliation, supplier specification
cp_output_mass	inspection_packaging	final_bearing_output	release scale and production record	product designation; net mass; accepted quantity; rejects; work in progress; shipment	Weigh net conforming bearings after release inspection and before transport packaging; reconcile production and shipment.	kg	each released batch	representative reporting period	all included bearing production sites	conforming net mass is denominator and normalized to 1 kg	scale calibration, inspection release, production and shipment reconciliation

Calculation Rules

rule_id	Applies to	Formula or rule	Inputs	Output	source_ids
calc_reference_normalization	all inventory rows	Divide each reporting-period exchange assigned to conforming bearings by net conforming bearing mass from the same period and boundary.	attributable exchange quantity; conforming output mass	exchange per 1 kg reference flow	eu-recommendation-2021-2279
calc_electricity_conversion	stage electricity rows	Multiply metered kWh by 3.6 while preserving the meter record and factor.	electricity in kWh	electricity in MJ
calc_water_mass	water rows	Multiply measured volume by a stated density appropriate to measured temperature and composition.	volume; temperature; water composition; density	water mass in kg
calc_direct_fossil_co2	fossil_co2_heat_treatment	Multiply metered fuel quantity by documented fossil-carbon or supplier emission factor and oxidation fraction; exclude upstream emissions.	fuel quantity; factor; oxidation fraction; unit conversions	direct fossil CO2 mass	eu-recommendation-2021-2279
calc_metal_balance	forming, turning, grinding, and final output	Reconcile alloy-specific steel input with conforming product, chips, swarf, rejects, retained work in progress, and documented stock change; investigate material imbalance.	alloy-specific material records	documented metal balance and discrepancy	skf-green-bearings

Data Quality Requirements

requirement_id	Applies to	Requirement	Evidence
dq_product_identity	reference product	Record bearing family, rolling-element type, principal dimensions, applicable load or tolerance class, seal or shield state, cage and ring materials, heat-treatment route, lubrication, and packaging state.	product specification, drawing, inspection and release record
dq_measurement	all measured rows	Prefer calibrated direct measurement and record instrument identity, resolution, calibration status, interval, missing-data treatment, and uncertainty.	calibration certificate, meter log, scale record, uncertainty note
dq_temporal	all foreground rows	Use a representative continuous 12-month period where available or justify a shorter campaign capturing batch and operating variability; align numerator and denominator periods.	reporting-period statement and representativeness assessment
dq_site_scope	all processes	Identify each included site and outsourced operation; do not omit a material step because it occurs off site.	site and supplier process map, contracts, purchasing records
dq_completeness	all inventory rows	Reconcile purchased materials, site records, wastes, direct emissions, and conforming output; identify and quantitatively justify every exclusion.	mass and energy reconciliations, exclusion register
dq_technology	all processes	Describe forming, machining, heat-treatment atmosphere and furnace, grinding and honing, cleaning, assembly, lubrication, preservation, inspection, and packaging technologies sufficiently to distinguish routes.	process specifications, equipment list, production instructions
dq_upstream_data	all purchased inputs	Match datasets to actual alloy, auxiliary grade, energy supply, water source, packaging, geography, technology, product state, and delivery boundary; document proxies and sensitivity.	dataset-selection log and sensitivity assessment

No external numeric inventory range is prescribed. Each row remains a foreground collection requirement until two mutually independent, original-text-verified sources with compatible product state, functional unit, and system boundary support a defensible empirical range.

9. Validation Rules

rule_id	Rule
validation_rule_1	Confirm that the declared product is a complete ball or roller bearing under the stated boundary and not a bearing housing, plain bearing, loose ball, loose roller, bearing unit, or spare part.
validation_rule_2	Confirm that the reference product is exactly 1 kg net conforming finished bearing at the factory gate and that packaging mass is excluded from that net mass.
validation_rule_3	Confirm that all five required manufacturing stages are represented, including outsourced stages, and that exclusions or non-applicable steps are explicitly justified.
validation_rule_4	Confirm that every inventory row is an atomic physical, chemical, waste, energy, or elementary exchange and that no umbrella utility, fuel, packaging, chemical, wastewater, residue, or emission row is used.
validation_rule_5	Confirm that forming, heat-treatment, and grinding electricity are collected and reported separately, even where an allocation procedure uses a shared meter.
validation_rule_6	Confirm that machining chips and grinding swarf remain separate waste flows and are not netted against bearing-steel input or combined with rejected bearings.
validation_rule_7	Confirm that direct fossil carbon dioxide represents only foreground gaseous-natural-gas combustion and excludes upstream energy-system emissions.
validation_rule_8	Confirm that the metal balance and the cleaning-water balance have been performed and that material discrepancies are documented.
validation_rule_9	Confirm that UUID-bearing rows match the audited TianGong English and Chinese base names, flow type, classification, flow property, unit group, and public state; unresolved rows must retain empty UUIDs and manifest review records.
validation_rule_10	Confirm that no externally inferred range is used unless at least two independent, original-text-verified sources have compatible boundaries, reference flow, product state, and units.

10. Published Dataset Profile

Field	Value
dataset_role	Cradle-to-factory-gate foreground data package for one declared complete ball or roller bearing product, normalized to net conforming mass
downstream_use	Linked product flow, unit-process dataset, manufacturer product footprint, EPD-supporting model, or life-cycle model whose downstream stages and scenarios are added separately
allowed_use	Comparison or aggregation only when product function, declared bearing specification, reference flow, geography, technology, reporting period, system boundary, allocation, and data quality are compatible
excluded_use	Direct representation of loose parts, bearing housings, plain bearings, bearing units outside the declared identity, use-phase performance, maintenance, remanufacturing, or end-of-life scenarios
required_metadata	Production geography and sites; reporting period; product designation and design; mass and dimensions; materials; manufacturing and outsourced routes; lubrication and preservation state; inspection basis; allocation; packaging; upstream dataset choices
required_quality_disclosure	Primary-data share and coverage; meter and scale evidence; missing data; exclusions; allocation drivers; mass, water, and energy reconciliations; proxy datasets; uncertainty; representativeness; unresolved UUIDs and range evidence
update_trigger	Material change in bearing design, mass, alloy, supplier route, manufacturing site or technology, furnace fuel, electricity supply, cleaning system, lubricant or preservation product, packaging, allocation, data coverage, or reporting period

11. Data Sources

Source id	Type	Reference	Used for
un-cpc-3-0-structure-2025	official_guidance	United Nations Statistics Division, CPC Ver. 3.0 Structure, 30 June 2025. https://unstats.un.org/unsd/classifications/Econ/Download/In%20Text/CPC_Ver_3.0_Structure_30Jun2025.csv	Original CSV row verified for CPC 43310 product classification identity.
un-cpc-1-1-chinese-2002	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	Original Chinese classification text verified for the professional title “滚珠轴承或滚柱轴承”.
international-epd-pcr-2023-03	standard	International EPD System, PCR 2023:03 Bearings, bearing units and parts. https://www.environdec.com/pcr-library/pcr_c8639225-b509-4a82-6b78-08d9caad768c	Official original landing page verified for category correspondence to UN CPC 4331 and the distinction of bearing production from downstream life-cycle stages.
skf-insert-bearings-18033	handbook	SKF, Insert bearings, publication 18033 EN. https://cdn.skfmediahub.skf.com/api/public/0901d196807f0c2f/pdf_preview_medium/Insert_bearings_booklet_-_18033_EN_pdf_preview_medium.pdf	Original PDF pages verified for heat treatment, grinding, honing, assembly, greasing or sealing, inspection, preservation, marking, and packaging operations.
skf-green-bearings	literature	SKF Evolution, Green bearings. https://cdn.skfmediahub.skf.com/api/public/0901d1968031d53b/pdf_preview_medium/0901d1968031d53b_pdf_preview_medium.pdf	Original full PDF verified for steel and auxiliary inputs, energy, water-based cleaning, lubrication, packaging, chips, grinding swarf, used oil, and waste handling.
eu-recommendation-2021-2279	official_guidance	European Commission Recommendation (EU) 2021/2279 on the use of the Environmental Footprint methods. https://eur-lex.europa.eu/eli/reco/2021/2279/2021-12-30/eng	Official original legal text verified for functional-unit definition, allocation hierarchy, data quality, and foreground inventory rules.