Are potential vendors screened or rated in any way?

Is there past experience with them? – (was it healthy?)
Do they have a full range of products? – (will you have to buy from more than one vendor?)
Can they provide service and support? – (is it included in your normal business activity pricing?)

Has an outside service been considered?

Are they capable of both product and maintenance support? – (does it cover all areas of your application needs?)
Do they offer cost per unit of output pricing? – (is it clearly defined and likely to be fairly administered?)
Will they account for problems and corrective action? – ( both in terms of service and end product quality issues?)

1. Define Air Filtration Objectives
2. Identify Contaminants to be Removed
3. Understand Operational Constraints
4. Consider Available Options
5. Checklist