Exception from fence height limitations. The Concord Zoning Board of Appeals may permit a fence up to eight feet in height in any rear yard, not a front yard equivalent, or in any side yard, not a required side yard, provided that such fence is at least 10 feet from any property line and that the following findings are made:
(a) That such fence shall not unduly shut out lights or air to adjoining properties.
(b) That such fence shall not create a fire hazard by reason of its construction or location.