Utah Code Title 78B. Judicial Code § 78B-5-821. Joinder of defendants

(1) A person seeking recovery, or any defendant who is a party to the litigation, may join as a defendant, in accordance with the Utah Rules of Civil Procedure, any person other than a person immune from suit alleged to have caused or contributed to the injury or damage for which recovery is sought, for the purpose of having determined their respective proportions of fault.

(2) A person immune from suit may not be named as a defendant, but fault may be allocated to a person immune from suit solely for the purpose of accurately determining the fault of the person seeking recovery and all defendants.  A person immune from suit is not subject to any liability, based on the allocation of fault, in this or any other action.

(4) Fault may not be allocated to a non-party unless a party timely files a description of the factual and legal basis on which fault can be allocated and information identifying the non-party, to the extent known or reasonably available to the party, including name, address, telephone number and employer.  The party shall file the description and identifying information in accordance with Rule 9, Utah Rules of Civil Procedure or as ordered by the court but in no event later than 90 days before trial as provided in Rule 9, Utah Rules of Civil Procedure.