It is unlawful for any person, firm or corporation holding any permit issued pursuant to the provisions of Sections 12.12.010 through 12.12.160 to fail, refuse or neglect to keep such permit at all times at the place where such building material or debris is deposited upon a public street, alley or other public place or to fail, refuse or neglect, upon demand therefor, to exhibit such permit to the superintendent of streets or to any of his inspectors or to any public officer. (Prior code § 12.20.110)