Within the Red Hat certification program, the RHCA is considered the most complete (and grueling) certification among the seven major Red Hat certifications. In fact, some equate the prestige of the RHCA to that of the Microsoft Certified Master and possibly the CCIE.
A plumbing fixture like a sink can not function properly without a sink vent. When a drain pipe drains it creates a negative pressure in the sink drain; the negative pressure will pull the water out of the p-trap of the sink that's draining and sewer gases can enter your home if a sink vent is not installed.
Revised by BoatUS editors in April 2012. A bilge blower is important not only because the USCG may require it, but also because your life may depend on it. The Coast Guard stipulates the use of a mechanical ventilation system for all non-open type boats built after July 31, 1980 which run on gasoline.