CRR 384/200
Joint industry programme on carbon monoxide issues:

Vitiation studies of an open-flued central heater boiler operated in compartments

BG Technology has conducted a series of tests to determine the behaviour of an open-flued central
heating boiler when operated with a fully blocked flue in compartments of various sizes. The objectives
were to assess the validity of the predictive oxygen vitiation alarm levels previously reported and to
provide data against which validation for the Combustion Product Gas Build-up Model.
The series of tests were carried out using a domestic central heating boiler deployed in compartments
installed into the BG Technology Test Facility, providing a configuration typical of that found in a
suburban house. The computerised data acquisition systems were deployed to monitor the air quality
within the compartment containing the boiler. Where the compartment was significantly larger than the appliance, either no vitiation occurred or the predictive vitiation level was attained prior to significant CO levels being observed. Where the compartment was of a similar volume to the appliance mounted inside, the vitiation was either rapid and severe, leading to the self-extinguishing of the appliance on timescales of less than three minutes, or the appliance operated with significant CO levels in the compartment. An explanation for the latter observation is offered.