Machinery & Utility Systems

What the group supplies

• Compressed air for tools, bulk transfer, instruments and engine starting.
• Heating, cooling and ventilation for accommodation, control rooms and drive rooms. The same systems pressurise safe areas against gas ingress.
• Fresh water for drinking, washing and drilling, made from seawater.
• Sewage treatment before overboard discharge.

Choosing between the sub-Categories

Air compressors and dryers covers screw and piston compressors, receivers and dryers. HVAC systems covers chillers, air handling units, fans and dampers. Water makers and purification covers reverse osmosis units, freshwater generators and treatment. Sewage treatment plants covers biological, membrane and electrochemical plants.

Sizing against persons on board

Water makers, sewage plants and accommodation HVAC scale with persons on board (POB). Size them to the maximum POB on the unit's certificate, not today's crew, and allow for temporary accommodation modules. Compressors scale with consumers, such as bulk transfer rate, instrument count and the number of engines that need starting air. A unit running at full output all the time wears faster and leaves no margin when a second unit is down.

Regulations across the group

MARPOL applies to drilling units because it counts platforms as ships.

• Annex IV requires a type-approved sewage treatment plant, a comminuting and disinfecting system or a holding tank. A treatment plant must meet the IMO standard in force when it is installed.
• Annex VI Regulation 12 prohibits new installations containing ozone-depleting substances. HCFCs such as R22 were permitted only until 1 January 2020, so a used R22 chiller or condensing unit cannot be fitted as a new installation today.
• Class rules cover machinery serving essential services, including starting air compressors and receivers.
• Equipment inside hazardous areas needs ATEX or IECEx certification for the zone, per IEC 60079 and IEC 61892-7.
• Pressure vessels, such as air receivers, dryer towers and chiller shells, need certificates to the design code and class rules.

Integration questions that cut across the group

Check supply voltage and frequency first, since many units are built for one or the other. Then check cooling water, which usually means seawater or the central fresh water system, and the materials it needs. Check control and alarm signals to the vessel's alarm and monitoring system. Check footprint, weight and access for maintenance. Units on deck need marine coatings and enclosure ratings suited to spray.

Records that make used utility plant credible

• Type approval certificates for sewage plants, and the IMO standard they cite
• Refrigerant type, charge and recovery records for any chiller or condensing unit
• Pressure vessel certificates and last inspection for receivers, dryer towers and chiller shells
• Running hours and overhaul history of compressors and high-pressure pumps
• Ex certificates for any motor, fan or panel meant for a hazardous zone
• Water quality and effluent test results from service

Missing records usually mean testing or re-certification before flag or class accepts the unit.

What matters most when sourcing used

The certificate often matters more than condition. An Annex IV plant with only an old type approval, or a chiller charged with R22, can be worth little however clean it is. After that, look at running hours on the main wear parts and when they were last replaced. Wear parts include compressor airends, refrigeration compressors, high-pressure pumps and membranes. Naventr passes your questions on capacity, hours and certificates to the Seller before you decide.