Retrofit : Retrofit Volume 1 Issue 2 2012
2 • RETROFIT AUSTRALIA • VOLUME 1 NUMBER 2 2012 | Company Profile Delivering controlled temperature water Rheem is often asked which is the best solution for applications requiring controlled temperature water, such as nursing homes, retirement villages, hospitals and hotels. There are three primary requirements to consider in selecting the right solution: • Safety • Initial capital outlay • Ongoing maintenance costs. Thermostatic mixing valves (TMVs) Systems using TMVs circulate water at temperatures exceeding 60°C around the building and temper at the bathroom to produce controlled temperature water at around 45°C to 50°C. • Two bathrooms are usually served by one TMV • TMVs are installed in cabinets to prevent tampering • To limit the potential for the growth of Legionella bacteria, the dead leg from the TMV to the tap must be as short as possible, and no more than 6 to 10 metres, depending on local regulations. Guardian warm water Guardian warm water is a centralised system that produces water at around 45°C to 50°C and circulates this around the building. • All warm water outlets are supplied from the one plant • Guardian is supplied in a lockable metal cabinet and located in a plant room to prevent tampering • To limit the potential for the growth of Legionella bacteria, the length of the dead leg from the ring main to the tap must be as short as possible, and no more than 6 to 10 metres, depending on local regulations. Safety All TMVs must be certified to AS4032.1. Rheem Guardian employs large-capacity TMVs that are certified to AS4032.1 and Rheem Guardian is listed as an approved warm water system with New South Wales Health. The temperatures produced by TMVs and Rheem Guardian are within the range that can support the growth of Legionella bacteria. Appropriate installation and maintenance practices are required with either system type. Rheem recommends the inclusion of a process of disinfection to manage the potential for Legionella growth. Initial capital costs The capital and installation cost of TMVs increases with the size of the establishment. Up to around 32 beds, TMVs provide a lower capital cost and installation investment; however, over this size, Rheem Guardian provides the lowest cost of compliance. Maintenance costs Unfortunately, maintenance costs are rarely considered at the design stage, where capital expenditure is divorced from running expenses. Both TMVs and Rheem Guardian have maintenance requirements. It is here that the benefits of Rheem Guardian dramatically outweigh those of TMVs, regardless of building size, as the maintenance is restricted to one centralised plant. Total life cycle cost analysis is shown below for a range of aged care facility sizes.1 Number of Beds 22 70 146 TMV Guardian TMV Guardian TMV Guardian Qty/model 11 80L/min 35 160L/min 73 240L/min Capital Cost $6900 $9400 $22,000 $14,000 $45,600 $19,000 Installation Cost $1375 $2700 $4375 $2700 $9125 $2700 Total Installed Cost $8275 $12,100 $26,375 $16,700 $44,725 $21,700 Yearly Maintenance Cost $2150 $1370 $6850 $2210 $14,270 $2520 10 yr Life Cycle Cost $29,760 $25,970 $94,690 $39,080 $197,500 $47,040 15 yr Life Cycle Cost $40,510 $32,810 $128,900 $50,120 $268,870 $59,640 1 LIFE CYCLE COST IS A COMBINATION OF CAPITAL COST, INSTALLATION COSTS AND MAINTENANCE COSTS. COSTS MAY VARY DEPENDING ON THE MODEL OF SYSTEM EMPLOYED, THE WATER CONDITIONS AND MAINTENANCE REGIME REQUIRED AND/OR EMPLOYED.
Retrofit Volume 1 2012
Retrofit Volume 2 Issue 1 2013