PROJECT RCC COOLING TOWER FOR 1 X 51 MW COMBINED CYCLE POWER PLANT FOR ONGC, HAZIRA

ENQUIRY T7B1O88410 & NIT No. 23749

DATE 8/8/2015
PRE BID QUERIES
SUB-SECTION / BHEL REPLY ON THE PRE BID
DESCRIPTION AS PER QUERIES BY HAMON SHRIRAM COTTRELL PVT. QUERIES
SL.NO. VOLUME / PART PAGE NO. /
SPECIFICATIONS LTD. DATED 20/08/2015 DATED 08.09.2015
CLAUSE NO.
I. TECH SPECIFICATION
Part 1 of 2 / Section I / 4 of Kindly confirm the painting specifications for the Bidder to note that Painting on RCC
PEMC-05255 70 / 1.4.0 Painting on concrete structures Cooling tower shall be done as per Clause
following (which is applicable for cooling tower for
Rev.01 shall be done as per Annexure-2 5.4.18 Doc. 5111168-ME-SPC-100-001
this project) :
Rev. 01 , Volume III seection 5 attached
(Volume III Section 5).
a)    Inside surface of RCC cold water basin and as Annexure 2 in the technical
RCC cold water outlet channel specification.

b)    Outside surface of RCC cold water basin and

1 RCC cold water outlet channel

c)    Inside surface of RCC superstructure

d)    Outside surface of RCC superstructure

e)    Whether the inside structure above hot water

distribution level needs to be painted or not ? (as
there will not be any spray of water in these area)

Part 1 of 2 / Kindly provide us the following on circulating water

Section I / 5 of
2 PEMC-05255 Make up water analysis & make up water to select the right kind of PVC
70 / 1.6.0
Rev.01 Film type fill.
Please note that Filtered water (make up
a)    Total Suspended Solids (TSS) water) analysis data is already furnished.
The same is available in the bid
document. Bidder to proceed with the
b)    Total Dissolved Solids (TDS) same.

c)    Cycle of concentration (COC) COC is 5

Kindly confirm whether the thermal design of our

proposed cooling tower can be of our (Hamon)
design or we should follow Fulkerson’s handbook
Part 1 of 2 /
Section I / 6 of Thermal analysis of cooling as mentioned in Annexure B (page 53 of 69 under Bidder to follow Fulkerson's handbook for
3 PEMC-05255
70 / 1.7.0 tower Part 2 of 2). Please note that there is no specific thermal design of cooling tower.
Rev.01
mentioning of the design calculations as per
Fulkerson’s calculations vide page no. 10 to 12 of
70 under section II. Kindly clarify.
 Maximum pumping head
Part 1 of 2 /
Section II / 13 of available at : 12 mwc We presume that the ground level refer to EL 101.2
4 PEMC-05255 Bidders understanding is correct.
70 / 2.4.16 ground level at terminal point of (FGL of new CCCPP area). Kindly confirm.
Rev.01
CT
Bidder to comply with the specification.
RCC partition wall shall be provided in
such a way that each cell can be taken
Part 1 of 2 / As there is no load on the partition wall, can we out of service without affecting the
Section II / 15 of
5 PEMC-05255 Partition wall in RCC. consider Pre-cast Concrete block wall? Kindly operations of the other cell.
70 / 2.7.5
Rev.01 confirm. Bidder to use cast in situ for partition
wall.

Part 1 of 2 /
Section II / 15 of For GRP fan stack, the stack door shall be of GRP.
6 PEMC-05255 Fan stack access door in MS. Noted.
70 / 2.7.7 Kindly confirm.
Rev.01

RCC staircase one each at both

Part 1 of 2 / Since the length of cooling tower is less than 50 Bidder to comply with the specification
Section II / 15 of the ends of the cooling tower
7 PEMC-05255 mtr., we suggest to have RCC staircase at one end requirement of two staircases, one at each
70 / 2.7.9 from ground level to fan deck
Rev.01 and cat ladder at the other end. Kindly confirm. end.
shall be provided.

CW pipes shall be Steel pipe

As per Terminal point and layout details
conforming to IS-3589 with
Part 1 of 2 / there is no buried pipe in the scope of
Section II / 17 of “Pipecoat ” or equivalent Kindly provide us the complete specifications such
8 PEMC-05255 work of bidder. Hence, underderground
70 / 2.9.0 coatings externally applied on as IS standard, thickness of coat etc.
Rev.01 piping with buried coating is not
buried / underground (u/g)
applicable.
pipes.

Kindly confirm us the following :

Buried pipe thickness shall be a)    Thickness of pipe having diameter varies from
designed as per AWWA M11 150 NB to 1400 NB to be required for the proposed Please note that there is no Buried pipe in
Part 1 of 2 / standard for Steel pipes. cooling tower. bidder's scope of supply.
Section II / 17 of
9 PEMC-05255 b)    Depth of buried pipe below finished ground Bidder shall follow PMS 11D for piping
70 / 2.9.0
Rev.01 Minimum corrosion allowance of level. specification which is for above ground
3.2 mm shall be provided for all c)    We shall consider the thickness of pipes as per piping. (Attached with this mail)
buried underground pipes. your clarifications and we shall not provide any
corrosion allowance for the buried pipe.

Bidder to follow PMS 11D which is

enclosed alongwith this document.
The material of construction for
Kindly provide us the complete specifications for
Part 1 of 2 / the valves, rubber expansion
Section II / 18 of valves, rubber expansion bellows, fittings etc. at
10 PEMC-05255 bellows, fittings provided shall
70 / 2.9.0 this stage itself, as this will have commercial
Rev.01 be subjected to Owner/Owner’s
implications.
representative’s approval.
 Part 1 of 2 / Please note that there is no Buried pipe in
Section II / 18 of Kindly provide us the detailed specifications for this
11 PEMC-05255 Cathode protection bidder's scope of supply. Hence cathodic
70 / 2.9.0 to enable us to consider our price accordingly.
Rev.01 protection is not applicable.

Bidder to comply with the specification

requirement of two vibration cut-off
Part 1 of 2 / Two vibration cut-off switches As a standard practice, one vibration cut off switch
Section II / 20 of switches with adjustment for sensitivity
12 PEMC-05255 with adjustment for sensitivity for each fan (ie one for each cell) shall be provided.
70 / 2.10.8 for each fan.
Rev.01 for each fan shall be provided. Kindly confirm.

Bidder to comply with the specification

Three nos. of Sludge cum
requirement of Three nos. of Sludge cum
Part 1 of 2 / dewatering pumps (one number As a standard practice, one sludge cum dewatering
Section II / 20 of dewatering pumps (one number for each
13 PEMC-05255 for each cell) along with motors pump per cooling tower shall be provided. Kindly
70 / 2.10.9 cell) along with motors and accessories.
Rev.01 and accessories shall be confirm.
provided.

Drift losses and power Drift loss value shall be indicative and not Noted.
Part 1 of 2 /
Section II / 21 of consumption shall be within the guarantee, as we shall not measure the drift loss
14 PEMC-05255
70 / 2.12.0 guaranteed limit mentioned in during performance guarantee testing of cooling
Rev.01
data sheets. tower. Kindly clarify.
Part 1 of 2 / FGL shall be EL 101.20
Section II / 23 of Water levels in CT basin & CW Kindly confirm the FGL for the proposed cooling
15 PEMC-05255
70 / 2.15.0 Pump sump tower, whether EL 99.70 or EL 101.20.
Rev.01

The soil investigation report

attached with this specification
Part 1 of 2 / Kindly provide us the final soil investigation report, Soil report is awaited from Agency and
Section III / 24 of is preliminary. The detailed soil
16 PEMC-05255 co-ordinates of cooling tower, existing ground level, will be furnished to bidders after receipt
70 / 3.2.0 investigation is being done by
Rev.01 cut off level of pile. from site.
BHEL and report will be
furnished later.

As per page no. 12 of 70, Margin for selection of fan

The motor name-plate rating at Bidder to note that margin for selection of
drive motor shall be 25% over the maximum input
Part 1 of 2 / site ambient shall have at least fan drive motor shall be 25% over the
Section IV / 35 of power requirement of the driven equipment. (i.e.
17 PEMC-05255 15% margin over the input max. input power requirement of the
70 / 4.8.1.1 drive shaft ) at rated duty point, whereas this is a
Rev.01 power requirement of the driven driven equipment (i.e. drive shaft ) at
contradictory with clause no.4.8.1.1 vide page
equipment at rated duty point. rated duty point.
no.35 of 70.

Insulation class : Motor shall

Part 1 of 2 / Bidder to note that Motors shall have
Section IV / 36 of have insulation class F with Insulation class contradicts with clause no.2.10.5,
18 PEMC-05255 class F insulation and limiting
70 / 4.8.1.7 temperature rise limited to class vide page 19 of 70.
Rev.01 temperature rise to class B limit.
B.

CW Basin is slightly higher than FGL of

the proposed CCCPP. However sludge
Part 1 of 2/ Since the cold water basin is above ground level,
19 3 of 31 / 1.5.0 Sludge pit cum dewatering pumps and sludge pits
PY51016 Rev.01 the sludge pit is not required. Kindly confirm.
are required in each of the cell of cooling
tower as specified in the specification.
 2 nos chain pulley blocks( one
Query is not relevant to the Specification
for handling screens and one for We shall consider manually operated, chain pulley
Part 1 of 2/ Point being referred to.
20 4 of 31 / 1.5.0 handling mechanical block butterfly wafer type, Cast Iron body valve and
PY51016 Rev.01 Bidder to comply with the specification
components at : Yes the standard shall be of BS 5155. Kindly confirm.
requirement.
Fan deck level)

As we are not finding side stream filters

Part 1 of 2/ Side Stream Filters & its specifications, we presume that side stream filters As per Specification, Side stream filters
21 6 of 31 / 1.5.0
PY51016 Rev.01 auxiliaries & its auxiliaries are not included in cooling tower are not in bidder's scope of supply.
vendor’s scope of supply.
The terminal point of hot water header is
Hot water - At ground level and
Part 1 of 2/ Kindly confirm whether the hot water common N: 814.690 and E: 1797.000 (approx) and
22 6 of 31 / 1.7.1 at a distance of 1.0 m from the
PY51016 Rev.01 header is at ground level or below ground level. elevation of bottom of pipe is: 0.5m above
edge of tower.
FGL.

Dewatering cum sludge pumps are

1)    Over flow pipe of each cell shall be terminated provided for removal of sludge and water
at drain pipe of the cell. from each cell. The discharge line of this
2)    Drain pipe of each cell shall be terminated at pump including valves are in bidder
Over flow and drain - At a common drain pipe / trench. scope. The outlet from each cell is
Part 1 of 2/
23 6 of 31 / 1.7.1 distance of 1.0 m from the edge 3)    We presume that the common drain pipe / connected to a drain header and terminal
PY51016 Rev.01
of tower. trench shall be terminated at a distance of 1 mtr. point for this line is at 1.0m from edge of
from the edge of the tower. cooling tower. The individual cell overflow
Kindly confirm whether our above understanding is lines are also connected to this drain
correct or not. header. For details refer to CW P&ID 2-
38101-04546.

Please note that the preliminary soil data

provided is that of other project within
Part 2 of 2/ Kindly confirm the Bore hole number applicable for
24 7 of 69 BH no.4,5,6,9 ONGC Plant premises. The data for the
PY51016 Rev.01 proposed cooling tower.
present cooling tower location will be
provided after receipt of data from site.

The coordinates of cooling tower (staircase

Part 2 of 2/ Kindly provide us the exact co-ordinates of cooling
25 49 of 69 CW & ACW Pump house layout end) at north west end are N: 813.190 E:
PY51016 Rev.01 tower.
1792.80.
V. OTHERS

After award of contract, our drawings / documents

Noted.
will be submitted to BHEL and we shall not
However, bidder's shall submit all
1 undertake any responsibility for getting approval
drawing / documents applicable for the
from your consultants like Fichtner / Engineers
package and get them approved by BHEL.
India Limited. Kindly confirm.
 Kindly confirm whether Pavement around the Please refer PEMC-05255 page 24 of 70
periphery of cooling tower is required or not ? If clause 3.1.0 Scope. Minimum 1.5m
2
required, kindly provide us the specifications and paving all round the periphery of cooling
width of pavement required. tower is required.

3 We request client to provide us the following :

1)    Free & uninterrupted construction water and

drinking water at site
2)    Free & uninterrupted construction power at
site Please refer attached the facility details
which shows scope demarcation between
3)    Free space for construction of our site office, Bidder and BHEL for all the facilities
labour hutment, store, stack yard for construction required.
materials and equipments.
4)    Approach road up to battery limit shall be
provided to us.

Cutting of trees, bushes etc. site levelling

5)    Cutting of trees, bushes etc., Site levelling and
and grading in cooling tower area are not
grading in cooling tower area.
in Bidder's scope of supply.

6)    Disposal of underground objects/services if

any (like pipes, cables, scraps, debris, slag, rock Noted.
etc) are to be cleared / rerouted by you before
construction of civil works.

The drain header shall be terminated at

1m away from the cooling tower for
7)    Drain trench for cooling tower, beyond the
further disposal by BHEL as indicated in
drain pipe.
the P&ID for cooling water system (Drg.
No. 2-38101-04546).