A business relationship is most often based on a signed agreement for the provision of services. Some decide to select other central IRBs who do not desire a contract rather than work through the legal issues. IRC has both a full contract form and a short indemnification form.
Downloadable contracts are available in the forms section.
IRC will require indemnification from the applicant. If the applicant is an investigator, indemnification must come from the sponsor. If the applicant is a sponsor with multiple sites, the indemnification must apply to all sites reviewed for the study. Indemnification is useless unless there is some assurance that the entity indemnifying has the ability to back it up when the time comes. IRC may ask for assurance of that ability.