Temporary use permits. It is recognized that it may be in accordance with the purpose of this chapter to permit temporary activities for a limited period of time, which activities may be prohibited by other provisions of this chapter. If such uses are of such a nature and are so located that at the time of petition they will in no way exert a detrimental effect upon the uses of land and activities normally permitted in the zone; or contribute materially to the general welfare of the Borough, particularly in a state of emergency, under conditions peculiar to the time and place involved; then the Board of Adjustment may, subject to all regulations for the issuance of special use permits elsewhere specified, direct the Zoning Inspector to issue a permit for a period not to exceed six months. Such period may be extended not more than for an additional period of six months.