Calculating the load on a lintel

I need to calculate the loads on a lintel for a 2 m gap in a solid 9" ground floor gable wall. Loads will be the bricks above and 5 first floor floor joists. I'd like to use a Catnic CN71A with a safe working load (SWL) of 20 kN.

1. First the floor joist load. Dead load is 0.75 kNm2, live load 1.5 kNm2, total 2.25 kNm2. Room area is 5.67m2 (2.1m x 2.7m) so load is 12.76 kN Number of joists is 8 (2.2m long), so number of end bearings is 16. Load per end bearing is 16/12.76 = 0.797 kN. End bearings on lintel are 5, so load is 4 kN.

Does this look ok?

1. Now the load from the wall. As an approximation can I take the triangular weight of the bricks above? What is the conversion from kg to kN, since 102 kg = 1 kN/m2, and I need kN and not kN/m2?

If it is a lot more complicated I'll get a structural engineer etc.

Thank you.