Hi I am currently writing up my own report and wondering if I have been asked for air flow rate/ extract rate certificate in accordance with part f by BC then will i need to work out and measure whole house ventilation rates or simply just test the fans in bathroom and cooker hood? I have been using the guidance document to write up my readings that i took with a testo 417 that i borrowed, but i am not sure if i should fill in and submit parts 1,2 and 3 or just keep it simple and give them part 3 - the flow rate measurements for bathroom and kitchens. Its for a conversion i am doing and they asking for it as the said it classed as new dwellings. I have look through some of the great stuff already on here but any other help would be amazing. I am a bit confused about the reference to whole house ventilation......do i need to include that or is that for when they ask you to do air tightness testing for part L? I think i managed to calculate the background ventilators and worked of the table to ensure they match the minimum required, so that was OK, i did it of the trickle vents in the windows and brick air vents in the walls. I am struggling to find examples of domestic air flow rate certificates. I found a few companies who can come and do it for me but i figured seeing as i could borrow the machine and do my self i would rather just right up my own report and see if BC except that? Also another bit that i was unsure about was a few comments that a certificate is required for each dwelling? Is that just a money making ploy and can i simply fill al the readings for both flats in the house on one report?