the external forces on the turbocharger and thus prevent excessive vibrations and possible damage. All
exhaust gas bellows must be of an approved type.
11.3.8
SCR-unit (11N03)
The exhaust gas piping must be straight at least 3...5 meters in front of the SCR unit. If both an exhaust
gas boiler and a SCR unit will be installed, then the exhaust gas boiler shall be installed after the SCR. Ar-
rangements must be made to ensure that water cannot spill down into the SCR, when the exhaust boiler
is cleaned with water.
In gas mode the SCR unit is not required as IMO Tier 3 and EPA Tier 4 are met.
11.3.9
Exhaust gas boiler
If exhaust gas boilers are installed, each engine should have a separate exhaust gas boiler. Alternatively,
a common boiler with separate gas sections for each engine is acceptable.
For dimensioning the boiler, the exhaust gas quantities and temperatures given in chapter Technical data
may be used.
11.3.10
Exhaust gas silencer (5R09)
The yard/designer should take into account that unfavorable layout of the exhaust system (length of straight
parts in the exhaust system) might cause amplification of the exhaust noise between engine outlet and the
silencer. Hence the attenuation of the silencer does not give any absolute guarantee for the noise level after
the silencer.
When included in the scope of supply, the standard silencer is of the absorption type, equipped with a
spark arrester. It is also provided with an explosion relief vent (option), a soot collector and a condense
drain, but it comes without mounting brackets and insulation. The silencer should be mounted vertically.
The noise attenuation of the standard silencer is either 25 or 35 dB(A).
Figure 11.8
Exhaust gas silencer (DAAE087980)
Table 11.1 Typical dimensions of exhaust gas silencers, Attenuation 35 dB (A)
Weight [kg]
B [mm]
A [mm]
D [mm]
L [mm]
NS
1690
260
635
1300
5510
600
2330
270
745
1500
6550
700
2750
280
840
1700
6530
800
3340
290
860
1800
7270
900
Flanges: DIN 2501
108
Product Guide Wärtsilä 34DF - 3/2012
Product Guide
11. Exhaust Gas System
