Background: I am conducting research into design services for a 36-inch special purpose aluminum pulpit ladder. The only moving parts are the wheels, which auto lock when stepped upon by the user. It doesn't plug in anywhere, and it'll be used between steel shelving in 36-inch aisles. We have an existing design for 34-inch aisles, https://www.fbo.gov/utils/view?id=47073d3f53e79d3fd563fd8533e321ab, we just need a design for the wider aisles. I've reached out to various vendors with my questions, but no luck getting responses. Questions: Can anyone tell me what kind of engineer I'd need to design such a ladder, and what certifications I should require? And it would be super helpful if someone can estimate the level of effort (labor hours) I should expect such a design to take? Thanks so much for your time!