Thanks for your question!
B1 refers to impacts of materials in use. Data in this field is still in its infancy and at present only concrete based materials will show some in-use impacts due to carbon sequestation at its surface. The standards and calculation methodologies are still under development within the industry and as the field matures we may see further impacts from say toxins in paints impacting on air quality and human toxicity (although at a global indicator level this is likely to be quite a small impact over buildings life cycle!)
In eTool B2 captures both maintenance (B2) and repair (B3), Maintenance impacts will come from eTool inputs for people and equipment, i.e. window cleaning tradestaff in our window templates. In materials we have options for repair interval and percentage of material repaired i.e. re-pointing in a brick wall template – 10% of the mortar in a will be repaired every 50 years.
Hope that helps!