SPX Cooling Technologies TG MAG15-50 1.4Technical conventions, Quantity, Symbol, Unit

1.4Technical conventions

Quantity	Symbol		Unit
Dynamic viscosity	µ		mPa.s = cP (Centipoise)
Kinematic viscosity	ν = µ			kg
		ρ	ρ = density	— 3
				[dm ]
				mm2
			ν = kinematic viscosity [ —s ] = cSt (Centistokes)
Note! In this manual only dynamic viscosity is used.
Pressure	p		[bar]
	∆p		Differential pressure = [bar]
	pm		Maximum pressure at discharge flange (design pressure) = [bar]
Note! In this manual, unless otherwise specified - pressure is relative pressure [bar].
Net Positive	NPSHa		Net Positive Suction Head is the total absolute inlet pressure at
SuctionHead			the pump suction connection, minus the vapour pressure of the
			pumped liquid.
			NPSHa is expressed in meter liquid column.
			It is the responsibility of the user to determine the NPSHa value.
	NPSHr		Net Positive Suction Head Required is the NPSH determined,
			after testing and calculation, by the pump manufacturer to avoid
			performance impairment due to cavitation within the pump at rate
			capacity.
			The NPSHr is measured at the suction flange, at the point where
			the capacity drop results in a pressure loss of at least 4%.

Note! In this manual, unless otherwise specified, NHPH = NPSHr

When selecting a pump, ensure that NPSHa is at least 1 m higher than the NPSHr.

A.0500.551 – IM-TGMAG/02.00 EN (02/2008) 11