Is there a number of minimum working hours for proving my work experience for HSP?

I worked with a company for 3+ years as an individual entrepreneur. My contact covers what kind of work i did, start and end dates of this contract. I have all tax declarations, a letter from colleague, contacts of senior accountant.
But it says nothing about how many hours i spent per week on average or minimum. Is it a problem? Maybe someone was in a situation like this.