Coating Reference Handbook - Hempel

HEMPEL
OPEN NOZZLE ABRASIVE BLASTING R1a
CAPACITY AND CONSUMPTION: (Indicative values)
AREA TYPE Sa 2 1/2 Sa 3
NON-METALLIC NON-METALLIC
ABRASIVE SQM pr ABRASIVE SQM pr
KG/SQM MAN-HOUR KG/SQM MAN-HOUR
NEW STEEL,
RUST GRADE A-B
Smooth 40 9 60 6
Normal 45 8 65 5.5
Complicated
SHOPPRIMED STEEL */
60 6 80 4.5
Smooth 30 12 50 7.5
Normal 35 10 55 6.5
Complicated
OLD STEEL,
RUST GRADE C-D
50 7.5 70 5
Smooth 50 7.5 70 5
Normal 60 6 80 4.5
Complicated 80 4.5 100 3.5
Figures are primarily based on practical experience with tankcoating jobs.
Abrasive blasting using 12 mm nozzles at 7-8 bars.
* / Some types of shopprimers are difficult to remove completely: PVB-types and
zinc-shopprimers. The latter will leave some zinc hammered on to the surface.
NOZZLES SIZE AND AIR REQUIREMENT: (Indicative values)
NOZZLE SIZE PRESSURE AT NOZZLE (Bars)
mm inch 4 4,6 5 6 7
8 1/3 3,0 3,2 3,5 4,0 4,6
9.5 5/16 4,0 4,5 - 5,5 6,5
10 3/8 4,6 - 5,7 6,4 7,2
11 7/16 5,5 6,1 6,8 7,5 9,1
12 1/2 6,7 - 8,2 9,3 10,4
AIR CONSUMPTION in cbm pr min
NOTE: Wear of nozzles quickly increases air requirement. Also other work, e.g.
grinders, airless pumps etc. may require air.
The Compressor should therefore have a 25-50% higher air capacity, than
required according to above table.
Venturi shaped nozzles are recommended for maximum efficiency.
They should remain undamaged and be replaced when their internal diameter
has worn approx. 1-2 mm.
Remember to check and empty oil- and water separators
frequently, before they run full.
INSPR1a, ed2 VALIDITY SUBJECT TO CONFIRMATION 30/04/97 EMi