Delay in or failure of performance of either party hereto shall not constitute a default hereunder or give rise to any claim for damage if and to the extent such delay or failure is caused by any event beyond the control of the party affected which the party had no reasonable way of preventing or grounds to anticipate, including but not limited to an act of war, natural disaster, fire, explosion, labor dispute. The affected party shall immediately notify the other party in writing of the causes and expected duration of any such occurrence.