Temporary use permits. It is recognized that it may be in accordance with the purposes of this chapter to permit temporary activities for a limited period of time, which uses 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 the petition they will in no way exert a detrimental effect upon the uses of land and activities normally permitted in the zone and will contribute materially to the welfare of the Borough, particularly in a state of emergency, under conditions peculiar to the time and place involved, then the Joint Planning/Board of Adjustment may, by resolution, after written application, subject to all regulations for the issuance of special permits elsewhere specified, issue a permit for a period not to exceed six months. Such period may be extended not more than once for an additional period of six months.