a） During storage or repositioning,RTP vessels should be placed only on firm level
surfaces that are free of stones,tools,and other small hard objects,since contact
with such objects can cause localized damage.
b） The support base surface should be nonporous and free of cracks,depressions,and
vertical projections.Reinforced concrete,trowel finished to American Concrete
Institute specifications（ACI-301-72,Section11.7.3,“Trowel Finish”）,is often used
as a support base.The support base should be flat to within 1/4 in.of a horizontal
plane.Local irregularities should not exceed 1/4 in.Sloping bases shall be equally
flat.
c） Each flat-bottom vessel should be set on a cushioning pad to minimize stress
caused by seams,shrinkage distortion,and/or support base or vessel bottom
irregularities.This pad should be 1/2 in.thick,closed cell elastomeric sponge
material of suitable composition and compression deflection range of 5 psi to 9
psi,resin or cement grout,petroleum-base masticnd mortar,or other suitable
conforming material that will cushion the vessel bottom over surface irregularities
of the support base or vessel bottom.
d） Where a vessel has a bottom drain,provisions should be made in the support base
with clearances so that contact will not occur between the support base and
nozzles or nozzle flanges.
e） Where a trench in a support base is required to accommodate bottom discharge
piping ,a structural trench cover should be installed flush with the top of the
support base to minimize the unsupported area of the vessel bottom.
f） All flatbottom vessels should be secured in place by bolting to the support base
through hold-down lugs.This precaution will minimize the chance of vessel
damage at nozzle locations and areas of other attachment due to movement of the
unit.
g） All vessel nozzles below the liquid level should be joined to piping through a
flexible connection or flexible piping system.
h） Valves that are attached to vessel nozzles should be independently supported so
that the weight of the valve or the force of closing and opening of a valve does not
transmit the total torque load directly to the nozzle.
i） Flanged connections should be made in accordance with the Fabricator’s
recommendations.Where the Fabricator’s recommendations are not available and
where a flanged pipe or fitting is attached to a vessel nozzle with a full-face
flange:
1）Fullface gaskets are to be used,per Fig.NM91.If the mating flange has a raised
face,it should be machined flat or a filler ring of the proper thickness should be
applied to provide a full flat surface for contact,per Fig.NM9-2.Gasket material
with hardness exceeding 65 durometer （ShoreA） should not be used.
2）Metal washers should be used under all bolt heads and nuts that would otherwise be
in contact with RTP flanges.
3） All flanges should be back spot faced.
4） Nut and bolt threads should be lubricated before tightening.
5） Bolting take-up torque should be applied uniformly and in accordance with the
sequence shown in Fig.NM93.Since the working pressure of a vessel covered by
ASME RTP-1 does not exceed 15 psig,limit bolt tightening torque to the values
shown in Fig.NM9-3
6） Where vertical or side entering agitation equipment is to be attached directly to a
vessel,design is required that is specific to that equipment and that
application.Side entering agitators should be independently supported.
7） Where heating apparatus （electrical tape,coils,or sparger） is to be installed,specific
detailed design of this equipment and its installation or attachment arrangements
should be approved by the vessel designer.
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