4 Loads of Equipment and Piping

4.1 General Requirements

4.1.1　Under normal operating conditions，the vertical loads of equipment shall typically include the following:

1　Self-weight of equipment；

2　Self-weight of accessories，connecting pipes，platforms and ladders supported on equipment and live loads acting on such platforms；

3　Self-weight of thermal insulation of equipment，accessories and connecting pipes；

4　Self-weight of supports of equipment；

5　Self-weight of medium inside of equipment and connecting pipes supported on equipment under normal operation；

6　Vertical force acting on equipment due to displacement，self-weight and sustained external loads on pipes connected to equipment under normal operation；

7　Vertical force acting on equipment by bellow expansion joints or other type of expansion joints due to internal pressure of medium and elastic force.

4.1.2　The horizontal loads of equipment can be classified into balanceable horizontal loads and un-balanceable horizontal loads.Load data shall be provided by the mechanical engineers based on specific operating conditions and types.The horizontal loads of equipment shall comply with the following requirements:

1　The following horizontal loads are balanceable horizontal loads occurring in pairs:

1）Frictional force acting on the movable support and frictional reaction force acting on the fixed support due to thermal expansion and cold contraction of equipment where the movable support and the fixed support are located at the same elevation and in the same straight line within the same structural unit；

2）Horizontal forces acting on the supports of equipment and the fixed supports of pipes due to displacement，selfweight and sustained external loads on the pipes where the supports of equipment and the fixed supports of the pipes connected to equipment are located at the same elevation and in the same straight line within the same structural unit；

3）When the scraper conveyor or belt conveyor is located within the same structural unit，horizontal force acting on the head of the transmission unit is offset by the sum of total frictional reaction force on the scraper or belt and horizontal force acting on the rear.

2　The following horizontal loads are unbalanceable horizontal loads:

1）Frictional force acting on the movable support and frictional reaction force acting on the fixed support due to thermal expansion and cold contraction of equipment where the movable support and the fixed support are not within the same structural unit or are within the same structural unit but not at the same elevation or in the same straight line.

2）Horizontal forces acting on the supports of equipment and the fixed supports of pipes due to displacement，selfweight and sustained external loads on pipes where the supports of equipment and the fixed supports of pipes connected to equipment are not within the same structural unit or are within the same structural unit but not at the same elevation or in the same straight line.

3）If the scraper conveyor or belt conveyer is not located within the same structural unit，horizontal force acting on the head of the transmission unit counteracts with the total frictional reaction partially，but cannot counteract the horizontal forces on the rear.

4.1.3　Under abnormal operating conditions，the following items shall be taken into account for the equipment loads:

1　Weightof accidental accumulation of pulverized coal，ash in equipment and weight of water filled in equipment during abnormal operating condition.

2　Weightof water filled in equipment and associated pipes connected on it during the hydraulic test.

3　Reaction force due to steam discharge.

4　Operating load and short-circuit current load of electrical equipment.

4.1.4　Wind loads and snow loads of outdoor equipment shall be calculated according to the current national standard Load Code for the Design of Building Structures GB 50009 and Chapters 7 and 8 in this code.

4.1.5　Where there is an external moment acting on the equipment，the force and/or moment acting on the equipment support caused by the external moment shall be calculated.

4.1.6　The loads of equipment shall be determined according to the following requirements:

1　In calculation of the characteristic value of equipment loads，self-weight of equipment shall be determined based on the data provided by the equipment manufacturer without any modification.

2　For reaction force acting on equipment due to steam discharge，the dynamic characteristics shall be considered and the dynamic coefficient may be taken as 1.1-1.2.

3　In the load design specification，a right-handed rectangular coordinate system shall be used as the fundamental coordinate system for force and moment.

4　Where the deaerator storage tank and horizontal heat exchanger are equipped with rolling（sliding）supports，the frictional force on the support can be calculated with the following equation:

where，Fm——frictional force on the support（kN）；

μ——friction coefficient；

Fz——vertical load on the support（kN）.

The friction coefficient μ can be selected as follows:

Sliding friction between steel and steel　μ=0.3

Sliding friction between steel and polytetrafluoroethylene　μ=0.2

Sliding friction between polytetrafluoroethylene and

polytetrafluoroethylene　μ=0.1

Rolling friction between steel and steel　μ=0.1

5　In addition to general loads on equipment under normal operating conditions，loads under abnormal operating conditions，accidental loads，wind loads，snow loads and earthquake actions shall also be considered in the equipment load design specification based on operating conditions and shall be indicated.Loads that are not indicated or specially noted shall be considered as variable loads under normal operating conditions.

4.1.7　The general vertical loads on pipes under normal operating conditions shall include the following:

1　Self-weight of pipes，including the self-weight of pipe metals，inner angle steels，stiffeners，inner struts and anti-wear parts，etc.

2　Self-weight of pipe components，such as valves，air dampers，flanges and its accessories，elbows，tees，flow measuring devices，expansion joints，flap valves，man holes，and other components.

3　Self-weight of thermal insulation structures of pipes and pipe components.

4　Self-weight of the access platform erected on the top of air and flue gas duct.

5　Weight of coal in the raw coal pipe downstream of coal feeder.

6　Weight of medium in pipes under normal operating conditions.

7　Vertical forces acting on the pipe by flexible fittings due to internal medium pressure and elastic force.

8　Reaction force due to displacement of pipes are restrained by hangers and supports，and the loads transferred by spring supports and hangers.

9　Vibration force that might be produced during normal operating condition of pipes.

4.1.8　Under normal operating conditions，general horizontal loads of pipes shall include the following:

1　Horizontal force due to displacement，self-weight and other sustained external loads of pipes.

2　Horizontal forces acting on the pipe by flexible fittings due to internal medium pressure and elastic force.

3　Frictional force acting on movable hangers and supports due to displacement of the pipe.

4　Horizontal vibration force that might be produced during normal operating condition of pipes.

4.1.9　The friction coefficient μ of pipe supports and hangers shall be determined in accordance with 4.1.6.μ can be 0.1 for hangers.