Rotating Equipment: Foundation Post-Pouring Concrete Inspection

This inscription is written to be a general guidelines for site rotating engineer to inspect the foundation prior equipment erection/installation.

After the civil team finish with the concrete pouring activity, it is recommended for the civil team to make Foundation Work Release Notice or Foundation Handover from civil to mechanical rotating. There are several items that the mechanical team should give some attention to, prior accepting the foundation, which will be discussed further below.

Foundation Handover Document

This handover document is necessary to keep the split of responsibility between the civil and mechanical team. For example, if there is still defect found prior to handover to mechanical team, then it is still the civil responsibility to repair the defect. Then, to identify whether the foundation is defectless or not, the mech rotating team should do two kinds of inspection, which are:

 

1.     Foundation centerline inspection

     This inspection is generally the same with the pre-pouring concrete inspection. To help with the inspection, I recommend to use a simple string/wire to mark the location. 

     The items that needed to be concerned with are:

• The coordinate of the foundation centerline
• The size of the foundation (length, width, diagonal)
• The  elevation of the TOC (top of concrete)
• The size of the anchor box (length, width, depth)
• The relative position of the anchor bolt
• The elevation of the anchor bolt (if using embedded anchor)

2.     Padding plate and Anchor Elevation check

This inspection adjective is to check the padding plate position and level, the tools that usuallty used in this inspection is an Auto Level Topcon. The items that needed to be concerned with are:

• The elevation of padding plate is correct and within  tolerance (+-3mm)
• The padding plate height shall not exceed 100mm relative from the Top Of Concrete
• The position of the skid is need to be considered during the setting position of the padding plate

If there are any defects found during these two inspection, then it is still the civil responsibility to repair it.  After both of the inspections are finish, then the foundation is good to go. 

The Foundation Handover Document pre-requisite documents are as follows :

1.     Pre-Pouring Inspection Report

2.     Concrete Compressive Test Report

3.     Foundation Centerline Inspection Report (witnessed by mech rotating team)

4.     Padding Plate and Anchor Elevation Check Report (witnessed by mech rotating team)

Please be aware that the common curing time for concrete is 28 days, so the equipment can be installed after 28 days, unless the civil team were using curing additive to their concrete mix. After Foundation Handover Document is signed by both parties (civil & mech rotating) then we can continued to prepare the next step.

Rotating Equipment: Foundation Pre-Pouring Concrete Inspection

This inscription is written to be a general guidelines for site engineer to inspect the foundation prior equipment erection/installation.

The best way to solve a problem is by preventing it. Perhaps this will be a little discomforting, considering that it is not at all a rotating engineer’s job to inspect the result of bekisting/formwork prior the concrete pouring.

Rotating engineer VS Civil engineer

The civil and rotating engineer have a very fundamental difference. Rotating engineer usually talks in micrometers while the civil engineer talks in centimeters.

In some case, to avoid any dispute regarding the foundation, it is recommended for the rotating engineer has more involvement in the foundation inspection activity.

I have experiences when the civil works is not satisfactory because the anchor holes position is deviated too far, the level is not right and anchor box size is not sufficient. This deviations were causing the corrective action to be very time consuming and costly.

Hence, to avoid the same mistake happening again, it is recommended that the rotating engineer is more involved in the pre-pouring concrete inspection.

Pre-requisite Documents

The pre-requisite documents used as reference on pre-pouring inspection are as follows:

1.     Plot plan drawing

2.     Foundation drawing

3.     Equipment general arrangement drawing

4.     Civil foundation standard drawing

5.     Inspection Checklist

Important Aspects

The aspect that needed to be focused on by rotating engineer on pre-pouring inspection are as follows:

1.     The coordinate of the foundation centerline

2.     The size of the foundation (length, width, diagonal)

3.     The  elevation of the TOC (top of concrete)

4.     The size of the anchor box (length, width, depth)

5.     The relative position of the anchor bolt

6.     The elevation of the anchor bolt (if using embedded anchor)

The deviation of the measurement shall not exceed 3 mm, while for anchor bolt position the deviation for each anchor position shall not exceed 1.5 mm.

Rotating Equipment : Equipment Preservation

This inscription is written to be a general guidelines for site engineer to generate preservation procedure routine to avoid some jammed governor, cranky bearing, excessive rust or seeping mech seal.

Some of the most common mistake happened on project site is the lack of care to the equipment well being during the inoperative condition. If the equipment is not well preserved during construction step, don’t be surprised if a lot of problems emerge during the commissioning step. This problems surely will be time consuming, time loss means more expenditure, more expenditure means less project profit, less project profit means less project bonus, I think that will be a sufficient motivation to any rotating equipment engineer to give a little extra attention to preservation precaution.

Preservation Oil

During the transportation of the equipment from the vendor workshop to the project site, it is very common that the bearing housing is emptied. After it is installed on its foundation, it is recommended to fill the oil as soon as possible. The oil will prevent the rusting on the inside of the housing.

Rotate the Equipment Shat

After the lube oil is filled, ensure to rotate the shaft routinely for several rotation, preferably once every week, with the final position shall be 270’ relative to initial position. This routine is necessary to avoid rust and damage on the shaft or bearing caused by prolonged loading on one side of the shaft.

Watertight Caps/Plugs

Before the piping is ready to be connected, ensure all opening (flange, nozzle, drain, vent, oiler, etc) is closed. It will prevent foreign material such as spatter, dust or corrosive agent to enter the inside of equipment. This aforementioned foreign material could cause damage to the mech seal or the internal lining.

Protective Covering

The equipment shall be protected from the surrounding construction activity, the covering is recommended to be designed to allow free air circulation and prevent collection of water. Some of the common protection materials can be used are the equipment packaging material or assemblies of scaffoldings.

Cleanness of the Equipment

As the old proverb said, cleanness is a part of the faith.

Preservative Coating

All kinds of exposed shaft, mounting foot, machined surface, etc shall be protective coatings. Grease, waxed cloth or typed A/B/D preservative is recommended as protective coating