methane
Enable an AI agent to recognise methane, assess its physical and chemical state in context, and determine which handling, use, containment or monitoring actions require further evidence.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex
Purpose and description
Enable an AI agent to recognise methane, assess its physical and chemical state in context, and determine which handling, use, containment or monitoring actions require further evidence.
It can be Identify and quantify methane using methods appropriate to the sample matrix and concentration range.; Track methane through storage, transport, dissolution, adsorption and release across named boundaries.; Assess whether evidence supports a proposed containment, transfer or phase-change action under applicable operating constraints.; Evaluate methane as an input to combustion or chemical conversion by linking its composition and state to a process model.; Detect and investigate methane accumulation or loss, retaining measurement uncertainty and sampling context.; Attribute methane origin or environmental fate while preserving unresolved alternatives..
Distinguishing features
An identity-specific analytical result supports CH4 rather than merely reporting a combustible gas; a broad gas alarm alone does not establish methane identity.
Molecular composition establishes one carbon atom and four hydrogen atoms per molecule, distinguishing methane from ethane, propane and other hydrocarbons.
Composition evidence distinguishes methane itself from natural gas or biogas, where methane is one constituent of a mixture.
Odour is not an identity test: pure methane is odourless, while supplied methane-containing gas may contain added odorants.
Biogenic, fossil-derived and synthetic methane share the same molecular identity; their origin requires provenance or suitable analytical evidence.
Scope
+ Chemical identification of methane and evidence distinguishing it from other gases
+ Methane quantity, concentration, purity and relevant impurities
+ Physical phase and thermodynamic conditions of an identified methane quantity
+ Conditions affecting methane release, combustion and oxygen displacement
+ Methane origin, transformations and transfers between containing systems or environmental reservoirs
- Natural gas, biogas and other fuel mixtures as complete products
- Design, certification and operation of tanks, pipelines, detectors and ventilation systems
- Microbial communities and geological formations that generate or consume methane
- Combustion appliances, engines and industrial conversion processes as systems
- Atmospheric climate models, emissions inventories and carbon accounting methodologies
Characteristics
- Chemical identity evidence
- CH4 confirmed | methane indicated | identity unresolved; include analytical method Prevents treating an unspecified gas response or fuel label as confirmed methane.
- Methane quantity
- mol or kg; volume only with temperature, pressure and reference basis Supports material balances and comparisons across storage or release conditions.
- Methane fraction
- mol/mol, volume fraction or mass fraction; explicitly identify basis and wet or dry reporting Distinguishes purity from concentration in a carrier mixture and prevents invalid comparisons.
- Accompanying substances
- Identified mixture constituents and measured fractions, including oxygen, water, carbon dioxide, other hydrocarbons and odorants where relevant Mixture composition changes interpretation of detection, use and hazard assessments.
- Physical occurrence
- Gas | liquid | solid | supercritical fluid | dissolved | adsorbed | hydrate-associated; multiple states may coexist Distinguishes methane phase from how methane is held in another material.
- Temperature and pressure
- K or degrees Celsius; Pa or bar with absolute or gauge basis stated Conditions determine phase interpretation, density and the meaning of reported gas volumes.
- Host or containing system
- Linked vessel, pipeline, pore space, water body, sediment, atmosphere or other identified host Locates methane and establishes boundaries for transfer, accumulation and release.
- Origin attribution
- Biogenic | thermogenic | other abiotic | synthetic | mixed | unresolved; retain supporting evidence Separates molecular identity from claims about how a methane quantity was formed.
- Methane transfer rate
- kg/s or mol/s across a named boundary over a stated interval Distinguishes stored methane from methane entering, leaving or escaping a system.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.methane
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 10 layers · 10 findings · 20 questions.
Methane identity and composition Establishes whether the material is methane and how methane relates to the sampled mixture.
Fuel names, odour and nonselective detector responses can be mistaken for methane-specific evidence.
Molecular identification
Records evidence supporting assignment to CH4.
Methane-specific evidence
Separates confirmed methane identity from an indication that could include other gases.
- What analytical evidence identifies CH4, and which plausible interfering substances does the method distinguish? definition
- Which sample, instrument, calibration and observation time support this identification? provenance
Purity and mixture context
Distinguishes a methane substance quantity from methane contained in a broader material.
Methane fraction and accompanying substances
Records methane abundance and other constituents needed to interpret the sample.
- What is the methane fraction, with what uncertainty, reporting basis and wet or dry convention? measurement
- Is the object being described a methane quantity or a mixture such as natural gas or biogas that needs its own linked model? boundary
Methane state and inventory Describes how much methane is present and the conditions under which it exists.
Methane volume and availability cannot be interpreted without thermodynamic conditions and its mode of occurrence.
Phase and host association
Records methane phase separately from dissolution, adsorption or hydrate association.
Observed methane occurrence
Connects physical occurrence to measured conditions and any host material.
- At the recorded temperature, pressure and composition, which methane phases or host associations are observed or inferred? measurement
- Is methane free, dissolved, adsorbed or hydrate-associated, and which host-material model describes its retention? boundary
Amount and volume basis
Makes methane inventories comparable across conditions.
Bounded methane inventory
Defines an amount within an explicit spatial and temporal boundary.
- How much methane lies within the stated boundary at the observation time, and what measurement or estimation supports that amount? measurement
- If quantity is reported as gas volume, what temperature, absolute pressure and compressibility treatment define that volume? measurement
Methane action conditions Records methane-specific conditions that constrain handling and use.
Methane identity alone does not establish whether a particular atmosphere, transfer or storage action is acceptable.
Combustible atmosphere context
Relates methane concentration to oxidant availability and the surrounding conditions.
Ignition assessment evidence
Collects the contextual evidence needed for an applicable combustible-atmosphere assessment.
- What methane and oxygen concentrations, diluents, temperature and pressure characterize the atmosphere being assessed? measurement
- Which validated criteria apply to these conditions, and what missing evidence prevents authorizing the proposed action? action
Release and exposure context
Connects methane occurrence to oxygen displacement, pressure release and cold-material exposure where relevant.
Handling constraints
Records conditions that a linked operating or safety model must resolve before handling.
- Could the identified methane quantity enter an occupied or confined space, and what observations establish oxygen availability and accumulation? boundary
- What pressure, temperature and release conditions must the linked equipment and operating models address before transfer or phase change? action
Methane origin and transformation Distinguishes methane formation history from reactions that consume or produce it.
Chemically identical methane can have different origins, while a change in methane quantity may reflect reaction rather than movement.
Formation attribution
Preserves evidence and competing explanations for methane origin.
Supported origin claim
Connects origin labels to supply records, formation context or analytical evidence.
- What records, isotopic measurements or associated-gas evidence support the proposed methane origin? provenance
- Could source mixing or subsequent transformation explain the same evidence, leaving origin unresolved? boundary
Chemical and biological conversion
Records methane production or consumption through a linked process.
Methane conversion account
Separates methane conversion from phase change, dilution and transfer.
- Which process produces or consumes methane, and what reactant, product or rate evidence supports that interpretation? measurement
- For a proposed conversion, what methane composition and state must the process model accept before the material can be used? action
Methane movement and environmental fate Tracks methane across containment and environmental boundaries.
A methane concentration observation does not by itself establish a leak rate, source or atmospheric emission.
Containment and transfer
Distinguishes intended methane movement from unintended escape.
Methane boundary crossing
Records the source, destination, timing and quantity of a methane transfer.
- Across which boundary is methane moving, and is the movement an intended transfer, vent, leak or unresolved event? boundary
- What methane-specific flow measurement or estimation establishes the transferred quantity and its uncertainty? measurement
Environmental observation
Connects methane measurements to reservoirs and possible transport or consumption pathways.
Concentration versus emission
Separates observed methane abundance from inferred source strength and eventual fate.
- Does the evidence describe a local concentration, reservoir inventory or flux, and what sampling extent and interval does it represent? measurement
- What transport and methane-consumption evidence is required to connect this observation to a source or an atmospheric release? boundary
What the second pass must settle
- Which methane identification and quantification methods should be accepted for each sample matrix, concentration range and interference profile?
- Which authoritative phase-property references and mixture models should support state and inventory calculations?
- Which jurisdictional and operational criteria should linked safety models apply to particular methane atmospheres and handling actions?
- How should isotopically labelled methane be represented without duplicating the registry's methane identity?
- What evidence and uncertainty rules are required to support origin attribution and conversion of environmental observations into methane emission estimates?