The two unsafe categories, the separate NCS description and how the assessment drives action.
An appliance can light normally and still be unsafe. Equally, a difference from a newer specification does not automatically establish danger. Classify from the actual findings and their combined effect.
ID identifies an immediate danger if the appliance or installation remains connected to gas. AR identifies potential danger from an established fault. These are the two GIUSP unsafe categories.
NCS may appear in business records for a standards shortfall assessed as safe. It is outside the current unsafe classifications. Never use it as a holding label when you have not established safety.
For example, a brief observation with no visible flue-product re-entry cannot by itself prove a poorly positioned terminal safe. A passed spillage check does not establish the integrity of every flue joint. Check the actual arrangement under relevant conditions and obtain competent guidance where needed.
Classification directs the action. Unresolved ID requires the disconnection and warning route; AR has separate routes depending on whether turning off will remove the risk. A customer request, repair cost or lack of replacement parts does not change the danger found.
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