What 45 kgf of holding force actually means
A rating is a laboratory statement. Site conditions are the variable.
Reading the specification honestly
The published figure is up to 45 kgf when attached to non-porous surfaces at 0.8 bar. 'Up to' and 'non-porous' are the operative words: it is a best-case figure under stated conditions, exactly as a lifting rating would be.
Why you should never work to the rated figure
Every real surface is worse than the test surface. Dust, texture, temperature, pad condition and curvature all reduce achievable force.
Treat the rating as a ceiling and work with margin, in the same way you would with any lifting or anchoring equipment. If the attachment feels marginal, it is.
Direction of load matters
Vacuum attachment is strongest in pure tension normal to the surface and weakest in shear, where the resistance is friction between pad and surface — a function of the clamping force and the surface condition.
On a vertical wall the tool's own weight acts in shear. That is a design case for the tool, but it is also why a contaminated surface is disproportionately dangerous vertically.
Questions about this
Will I actually get 45 kgf on site?
Rarely. That is a best-case figure on a non-porous surface at full working vacuum. Real surfaces are dustier, more textured and less flat, so treat the rating as a ceiling and work with margin.
Is the tool weaker in shear than in tension?
Yes. Vacuum attachment is strongest in pure tension normal to the surface. In shear the resistance is friction between pad and surface, which is why a contaminated surface is disproportionately risky on a vertical face.