Equipment and pipework that has a maximum design temperature within the range 800°F-1,115°F (425°C-600°C) and is fabricated from P-No.4, P-No.5A or P-No.5C materials, shall be of controlled purity and designed and fabricated to minimize in-service temper embrittlement and low creep ductility HAZ cracking. The following requirements shall be met: