The waste streams in most large plants can be classified under the following four basic sewer systems: the oily water sewer, the acid sewer, the storm water sewer and the sanitary sewer. Fire water from hoses is included in the estimated maximum flow quantities within unit areas containing hazardous hydrocarbon or chemical equipment. Pump blocks should have an open-end drain hub to collect pump casing drains, drainage from gland and seal piping at pumps, and drains in pump suction and discharge piping. Acid waste should be run in a separate sewer from alkaline waste. Acid and alkaline waste should be run as two separate sewer systems to the battery limit and the acid treating facility or a neutralizing sump. The storm water sewer collects maximum surface drainage including rainfall, wash water that is not contaminated, and cooling water that is not returned in return headers to cooling water facilities.