Electrical Design Requirements for Industrial Building

in the previous topic,Electrical Design Philosophy for Major Types of Buildings, we talk about the different types of buildings and how the building type (function) influence its electrical design

today, I will explain the first type of buildings which is industrial building and clarify the electrical requirements of this type of buildings.

Industrial building definition: 

A building designed to house industrial operations and provides the necessary conditions for workers and the operation of industrial equipment.

Types of industrial building: 

1- Factory - Flex Space (see fig.1)

Buildings that may have 10- to 22-foot clear ceiling height with dock height and drive-in loading, and extra parking. These buildings may include a variation in space utilization, ranging from office and retail through distribution, light industrial and occasional heavy industrial uses. They are designed to allow conversion of industrial units to a high percentage of office space.

 

fig (1)

2- Factory- Manufacturing (also called Heavy Industrial)(see fig.2)

Auto making, textiles, steel, chemicals, and food processing are typical uses of such properties. Typically zero to five percent office space. 

 

fig (2)

3- Factory - Office Showroom (see fig.3)

Single story (or mezzanine) buildings with 10 to 16 foot clear ceiling height, frontage treatment on one side and dock height or drive-in loading on the other. These buildings usually contain less than 15 percent office space. 

 

fig(3)

4- Research and Development (R&D)

Facilities generally used in high technology markets, broadly defined to include wide variations in markets across the country. R & D properties could have lab facilities, offices, warehouse facilities, or services such as carpentry or machine repair. Typically, each property allows a variable combination of office and other uses. The percentage of office space ranges from 20 to 100 percent, depending on the market and individual needs of the user.

5- Self-Storage/Mini-Storage Facility(see fig.4)

a building that provides personal storage for lease by consumers.

 

fig(4)

6- Truck Terminal/Hub/Transit Facility (see fig.5)

A specialized warehouse designed for loading and unloading and short term storage of goods. A truck terminal contains an unusually high number of loading docks for its size enabling simultaneous loading and unloading of a high volume of goods.

 

fig (5)

7- Factory-Warehouse (see fig.6)

A building used to receive and store goods and merchandise. In terms of classifying such property, warehouses are normally located in an area zoned for either commercial or industrial property.

 

fig (6)

8- Distribution Warehouse (see fig.7)

(also called Light Industrial) generally the least intense industrial use. Office use is limited to management tasks for the distribution or warehouse facility, or about 15 percent of total space.

 

fig (7)

9- Refrigerated/Cold Storage (see fig.8)

Buildings containing refrigerator or freezer space within the warehouse for storage of goods with specific low temperature storage requirements.

 

fig (9)

Electrical Drawings Details - Group no.(7)

Electrical Drawings Details - Group no.(7) 

This group will include the following Electrical Drawing Details:

• TRUNKING SYSTEM ARRANGEMENT DRAWING DETAIL 

• EARTHROD DRAWING DETAIL 

• CABLE TO EARTHROD CONNECTION (THERMOWELD) DRAWING DETAIL 

• CONNECTION OF EARTH PIT TO REINFORCEMENT AT GROUND LEVEL DRAWING DETAIL 

• TEE CONNECTION (T) & CROSS BONDING CONNECTION (CBC) DRAWING DETAIL 

• STEEL REBAR TO CABLE CONNECTING PONT (RB) DRAWING DETAIL 

• TYPICAL DETAILS OF EARTHING CABLE TO STEEL BAR CONNECTION DRAWING DETAIL 

• ROOF PENETRATION DRAWING DETAIL (CONDUIT SYSTEM) 

• STREET AND AREA LIGHTING DISTRIBUTION PILLAR DRAWING DETAIL 

• CABLE TERMINATION AT FUSE BOX DRAWING DETAIL 

• MANHOLE GROUNDING DRAWING DETAIL 

• GROUND ELECTRODE ASSEMBLY DRAWING DETAIL 

• AIR TERMINAL DRAWING DETAIL 

• SWIMMING POOL SCHEMATIC GROUNDING SYSTEM DRAWING DETAIL 

• STREET AND AREA LIGHTING DISTRIBUTION PILLAR DRAWING DETAIL 

• FLUSH FLOOR TRUNKING SYSTEM DRAWING DETAIL 

to download the Electrical Drawings Details - Group no.(7), please click Here or Here .

need more Electrical Drawings Details, please follow the below link:

Electrical Drawing Details - main page

Conference System - Part Two

As I mention in the previous topic that Audio Conference System Is Divided into Three Main Systems according To the Method of Control of the direct Connection between chairman ans delegates as follows:

1. Open Conference Systems.
2. Partially Open Conference Systems.
3. Controlled Conference Systems.

and I explain the open conference system in previous topic, now ,in this topic, I will continue explaining the other types of Conference systems as follows:

Partially Open Conference Systems: 

This System Is Suitable For Conferences with a Limited Number of Delegates to Speech Each Other but Under the Control of the Conference's Chairman.

 

The Sound Systems Permits Every Delegate To Speech To Other Delegates And Chairman Under The Control Of The Chairman So That The Chairman Can Switch Off The Speech Circuits Of The Talked Delegate And Other Delegates And Activate His Speech Circuit By switching On A Priority Button On His Unit.



Types of partially open Conference Systems: 

1- without internal and external broadcasting:
- In This Case Delegate Unit Contains:

• Microphone 
• Talk Button 
• Internal loud speaker 

- And Chairman Unit Contains:

• Microphone 
• Talk Button 
• Priority button 
• Internal loud speaker 

2- With internal and external broadcasting:

In this type, the external broadcasting is provided by adding a remote loud speaker to different remote locations while the internal broadcasting is done by using one of the following methods:

The addition of Side Sound Columns in the conference Hall and in this case Delegate Unit Contains only the Microphone and Talk Button And Chairman unit contain only the Microphone , Talk Button and Priority button.

Or Providing the Delegates and Chairman Units with an Internal Speaker (Recommended) as in type #1.




Controlled Conference Systems: 

This System Is Suitable For Conferences With A Large Number Of Delegates To Speech Each Other But Under The Full Control Of The Conference's Chairman.

This System Is Used When Speech Between Delegates Is Not Desired So In This System The Chairman Has A Control Panel (Permission Keys) Which Contains A Large Number Of Push Buttons And Lamps According To Max. Number of the Conference Hall Seats.

And If Any Delegate Wants To Speech He Will switch On A request Button In His Unit Hence, His Lamp in The Chairman's Control Panel Switch On Then The Chairman switch On The permission Button (which is below the lamp) Of This Delegate So, The Delegate Can Talk To Others Until The Chairman switch off The Button Again To Switch Off The Speech Circuit Of This Delegate.




Types of Controlled Conference Systems:

1- without internal and external broadcasting: (see fig.1)

In This system we can monitor the conference by providing the Delegates and Chairman Units with an Internal Speaker.

 

fig (1)

- In This Case Delegate Unit Contains:

• Microphone 
• Request Button. 
• Internal speaker. 

- And Chairman Unit Contains:

• Microphone 
• Permission keys control panel. 
• Internal speaker. 

2- With internal and external broadcasting: (see fig.2)

In this type, the external broadcasting is provided by adding a remote loud speaker to different remote locations while the internal broadcasting is done by using one of the following methods:

 

fig (2)

The addition of Side Sound Columns in the conference Hall and in this case Delegate Unit Contains only the Microphone , and Request button And Chairman unit contain only the Microphone , Permission keys control panel.

Or Providing the Delegates and Chairman Units with an Internal Speaker (Recommended) as in type #1. (see fig.2)



Notes:

• It can be useful to use one or more recorder to record the events of the conference. 
• Delegates units may be connected all in series or each row is connected in series then the rows are connected to the power amplifier separately. 

in the next topic , i will begin explaining the basics of sound system design. please, don't miss the coming topics.

Record Drawings

The terms record drawings, as-built drawings are often confused or misused. Record drawings should not be mistaken for as-built drawings since their definitions are different as follows:


As-built drawings :are those prepared by the contractor as it constructs the project and upon which it documents all changes made in the original contract documents during the construction process, and show the exact dimensions, geometry, and location of all elements of the work completed under the contract. These drawings are typically turned over to the consultant or client at the completion of the project. Sometimes others named it as “as fitted” or “as installed” drawings.



Record drawings: are those drawings prepared by the consultant when contracted to do so. These are usually a compendium of the original drawings, site changes known to the architect and information taken from the contractor’s as-built drawings. It is the one that shows the final condition of the building

 

PURPOSE FOR “RECORD” DRAWINGS

• Record drawings serve as a reference tool for future location and for inclusion within the Operations & Maintenance Manuals (O&M). 

DRAFTING INSTRUCTIONS FOR “RECORD” DRAWINGS

• A copy of complete set of the As-Built drawings is to be utilized as the base sheets for the record drawings. 
• The drawing numbers must remain the same as the originals & As-built for storage and retrieval purposes. 
• The Construction Revisions block, must describe in adequate detail what was removed or changed. 
• “Record” drawings must be stand alone documents and contain as much of the original information as possible plus all of the information concerning changes due to construction revisions. 

RESPONSIBILITY FOR “RECORD” DRAWINGS DELIVERY
A consultant, who is engaged for general review services for both code and non-code related work, should verify by letter to the Owner that the Work is complete and incorporate all changes onto to original drawings in the “Record drawings”.


PROCEDURES & RESPONSABILITIES FOR “RECORD” DRAWINGS

1- PROCEDURES & RESPONSABILITIES DURING CONTRACTING PHASE

• Consultant should arrange with their clients prior to executing contracts as to requirements for record drawings at the close of the project. 
• Consultant should be advising their clients that providing “record drawings” is an additional services and the appropriate cost should be included in their fees to the client. 
• A consultant, who is engaged for general review, should discuss with his client at the outset of the project whether or not the client will require record drawings, the format required, the extent of detail and degree of accuracy in specific areas if required and whether these will include: 

1. Transference of information from the contractor’s as-built drawings 
2. Incorporation of known site variants not shown on as-built drawings 
3. Incorporation of addenda into the originals 
4. Incorporation of change orders into the originals 
5. Incorporation of site instructions into the original 

• A consultant, who is not engaged to provide general review services for both code and non-code related work, should advise their client that they are not in a position to prepare record drawings since they will not be aware of all changes during construction.

2- PROCEDURES & RESPONSIBILITIES AT COMPLETION

• At completion of the project, The Contractor shall check all As- Built drawings and certify in writing on the title sheet of these drawings that they are complete and correct, prior to submission to the consultant. 
• The consultant shall review the As Built drawings and verify by letter to the Owner that the Work is complete and incorporate all changes onto to original drawings in “Record drawings”. 

NOTES:

• It is prudent to determine whether the client requires the consultant to generate the record set of drawings, how many copies will be required as well as the medium, prior to finalizing the Client/ consultant Contract rather than leaving it for discussion at the end of the project. 

• The Contractor may make a written request for copies of the completed Record Drawings. 

• Generally the consultant is responsible for producing the record drawings and should sign and seal them. It is also important that if the consultant did not personally observe and confirm the record conditions or have it done under his direct supervisory control and responsible charge, then he cannot sign and seal without clearly indicating the source of the information. The statement may be that the field changes noted is from mark-up drawings supplied by the owner or contractor. 

• It is important that the Consultant not represent that the record drawings are claiming to be the way that the building was in fact constructed. The following sample statement placed on the record drawing illustrates this principle: 

1. "The issuance of this record drawing is a representation by the architect that the construction, enlargement or alteration of the building is in general, as opposed to precise, conformity with the design prepared and provided by the architect, but is not a representation that the construction, enlargement or alteration of the building is in conformity with a design that has been prepared or provided by others." 
2. "The revisions to these contract documents, reflecting the significant changes in the Work made during construction, are based on data furnished by the contractor to the architect. The architect shall not be held responsible for the accuracy or completeness of the information provided by the contractor." 

In the next topic, i will explain how the Numbering system for drawings be done. please, keep following.

Schedule of Execution (SOE)

Schedule of Execution (SOE) definition:

It is a document representing the construction program and detailing the relevant activities, dates, allocation of labor and plant resources, etc.

The Contractor shall complete the work and services of the project to be executed under the contract in accordance with the schedule of execution.


Types of Schedule of Execution (SOE)
There are (2) different forms of Schedule of Execution as follow:

• Tabular form.

• Graphical form.

1- Tabular form: see fig.1

It is the simplest form used for presentation of schedule of execution.


Example:

fig (1): simple Tabular form

The chart in Fig.1 indicates that site preparation will start before the construction of pump house and it programmed to take (4) weeks and then the construction of pump house will begin.

Tabular form Advantages:

• This method has the advantage of being simple. 
• It is a convenient way to advise the Contractor of necessary material delivery dates. 
• It can be used for a small-scale project. 

Tabular form Disadvantages:

• For a large-scale project this method will not be able to represent all relevant activities of the project and In this case, graphical form must to be used. 

2- Graphical form : see fig.2

The graphical form is generally used because of ease in visualization. The most widely used graphical presentation of schedule of execution is the rectangular bar chart which sometimes called milestone bar chart or Gantt chart


Graphical form Construction:  see fig.2

the graphical form include (3) main parts as follows:

• A horizontal axis representing the total time span of the project, broken down into increments (days, weeks, or months).

• A vertical axis representing the tasks that make up the project.

• A graph area which contains horizontal bars for each task connecting the period start and period ending symbols. 

fig (2): Graphical form

Graphical form purposes:

• It represents the phases and activities of a project, so they can be understood by a wide audience all over the world. 
• It represents part of the triple constraints (cost, time and scope) of projects, because they focus primarily on schedule management.
• It usually used for top level reporting so management does not become bogged down in the minutia of the project or projects.
• It is used for monitoring a project's progress; it lets you see immediately what should have been achieved at any point in time.

Graphical form Advantages:

• It shows starting and completion dates for each item of work. 
• It indicates the items on which work must proceed concurrently 
• It indicates the items that overlap others and by how much. 
• It indicates the items that must be completed before work on others can begin. 
• It can be used for comparing performance of work with that scheduled by placing a bar above the schedule bar showing actual start and completion dates. 

Graphical form Disadvantages:

• It does not represent the size of a project or the relative size of work elements, therefore the magnitude of a behind-schedule condition is easily miscommunicated. 
• When displaying a large number of works activity dependencies may result in a unreadable chart. 
• Because the horizontal bars have a fixed height, they can misrepresent resource ( team responsibilities) requirements of a project, which may cause confusion especially in large projects. 

Example : see fig.2

The chart in fig used for a Security and Access Control project. Tasks are outlined in two sections. Each task uses a yellow triangle to indicate the start date of the task and a green down triangle to indicate the finish date of the task. Also shown on this schedule are the responsible sub-contractors for the project (in the column labeled R-E-S-P).



Schedule of Execution Terminology
Budget
A fiscal plan of operations for a given time period.
Baseline The project's original plan. Usually, the project's first set of start and finish dates.
Dependencies

an essential concept that some activities are dependent on other activities being completed first.
Milestone
An important event.
Resources

for team projects, it often helps to have an additional column containing numbers or initials which identify who on the team is responsible for the task.
Task List 

The list of steps in a project.
Statement of Work (SOW)

A document describing the work to be done on the contract.
Status

the projects progress, the chart is updated by filling in the task's bar to a length proportional to the amount of work finished.
Work Breakdown Structure (WBS)

A tree-like representation of the work to be done on a project. The WBS graphically shows the division of work.



in the next topic,i will clarify another tender documents called " Bidding Schedule". please, keep following

Circuit Breaker Definitions - Article 100

Circuit Breaker: see fig.1

A device designed to open and close a circuit by non-automatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating.

 

fig (1) : different types of circuit breakers

FPN: The automatic opening means can be integral, direct acting with the circuit breaker, or remote from the circuit breaker.

Or
A switching device capable of making, carrying, and interrupting currents under normal circuit conditions, and also of making, carrying for a specified time, and interrupting currents under specified abnormal circuit conditions, such as those of short circuit.

Adjustable (as applied to circuit breakers):  see fig.2 & 3

A qualifying term indicating that the circuit breaker can be set to trip at various values of current, time, or both, within a predetermined range. 

fig (2): Adjustable settings of Adjustable circuit breaker

Nonadjustable (as applied to circuit breakers):  see fig.3


A qualifying term indicating that the circuit breaker does not have any adjustment to alter the value of current at which it will trip or the time required for its operation. 

 

fig (3)

Interchangeable (as applied to circuit breakers):  see fig.3 

The user cannot change the trip unit in many circuit breakers, but some circuit breakers have an interchangeable trip unit, this feature allows the user to change the continuous current rating of the breaker without replacing the breaker, this is done by replacing the trip unit with one of a different rating. 

Instantaneous Trip (as applied to circuit breakers):  see fig.4

A qualifying term indicating that no delay is purposely introduced in the tripping action of the circuit breaker.

 

fig (4): please, study the curves ,and try to know the difference

 between Instantaneous and inverse time, and write it in the comments. 

Inverse Time (as applied to circuit breakers):  see fig.4 

A qualifying term indicating that there is purposely introduced a delay in the tripping action of the circuit breaker, which delay decreases as the magnitude of the current increases.


Setting (of circuit breakers):  see fig.2

The value of current, time, or both, at which an adjustable circuit breaker is set to trip.



Device:  see fig.5 & 6

A unit of an electrical system that is intended to carry but not utilize electric energy. 

 

fig (5): Devices but not act as disconnecting means

Components (such as switches, circuit breakers, fuseholders, receptacles, attachment plugs, and lampholders) that distribute or control but do not consume electricity are considered devices.



Disconnecting Means:
A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.

fig (5): Devices and act as disconnecting means

In the next topic , new definitions from NEC Code Article 100 will be highlighted.

Electrical Design Philosophy for Major Types of Buildings

Electrical Design Philosophy for Major Types of Buildings:

Introduction:

fig (1)

Look around in your region, you will discover that a lot of different size buildings surround you and of course each one of them is constructed for a certain purpose (see fig.1), these different purposes give us a guide for classification of these buildings i.e. all these Buildings will be classified according to their usage but before we list different types of buildings, we need to focus on the following Important facts about buildings: 

• Buildings are usually created for a specific function; A building's function strongly influences its design and construction. 

• A building is a product, a product is not more than a packaging of functions, and you must have best design & good selection of product materials to realize its best functions and to get a product (building) satisfy your anticipations. 

• Design is information processing, Output is not a building, but information to enable others to utilize that building. 

Why an electrical designer must be familiar with the Major Types of buildings?
That is because that the electrical network configuration is determined dependent on the requirements resulting from the building’s use and other additional factors which makes every building to be unique in its own way.

As professionals want to make efficient Electrical Design, it is important to have a preliminary imagination for every building type and that we will do in the following topics.




Major Types of buildings: see fig.2

1. Industrial buildings 
2. Commercial buildings 
3. Residential buildings 
4. Agricultural buildings 
5. Educational buildings 
6. Transportation buildings 
7. Religious buildings 
8. Parking and storage 
9. Military buildings 
10. Governmental buildings 
11. Cultural buildings 
12. Other buildings 

fig (2):  Major Types of buildings

1- Industrial buildings:
A building designed to house industrial operations and provides the necessary conditions for workers and the operation of industrial equipment.

2- Commercial buildings:
A building with more than 50 percent of its floor space used for commercial activities. Commercial buildings include, but are not limited to, office buildings, industrial property, medical centers, hotels, malls, retail stores, shopping centers, farm land, multifamily housing buildings, warehouses, and garages.

3- Residential buildings:
A building used or designed to be used in whole or in part for residential purposes and includes an associated outbuilding of and other improvement to a building used or designed to be used in whole or in part for residential purposes, but does not include a floating mobile home.

4- Agricultural buildings :
Agricultural buildings are structures designed for farming and agricultural practices, including but not limited to: growing and harvesting of crops and raising livestock and small animals.

5- Educational buildings :
Buildings used for academic or technical classroom instruction, such as elementary, middle, or high schools, and classroom buildings on college or university campuses.

Buildings on education campuses for which the main use is not classroom are included in the category relating to their use. For example, administration buildings are part of “Office”, dormitories are “Lodging”, and libraries are “Public Assembly”.

6- Transportation buildings :
A building Include machines that used as means of transportation, they include, but are not limited to, railway station, airports, and sea ports.

7- Religious buildings: 
Buildings in which people gather for religious activities, (such as chapels, churches, mosques, synagogues, and temples)

8- Parking and storage: 
A building /Space in which to park vehicles.

9- Military buildings :
They are any structure designed to house functions performed by a military unit.

10-Governmental buildings :
A building that houses a branch of government.

11-Cultural buildings:
A building contain any type of Cultural Heritage they include, but are not limited to, museums, libraries, theaters, cinemas.

12-Other buildings:
A building that is not included in all building types above like mobile homes.



Buildings’ Basic electrical design philosophy :see fig.3

fig (3):Examples for different types of building use 

and their impact on electric design Philosophy 

The following basic considerations are fundamental to any power system design:

1- Basic Safety:
The power system must be able to perform all of its basic functions, and withstand basic abnormal conditions, without damage to the system or to personnel.

2- Basic Functionality:
The power system must be able to distribute power from the source to the connected loads in a reliable manner under normal conditions.

3- Reasonable Cost:
The power system cost to obtain basic safety and functionality should be reasonable.

4- Code Compliance:
All applicable codes must be complied with.


Above and beyond the basics are a multitude of considerations, some of which will apply to each particular system design:

1- Enhanced Safety:
The ability to withstand extremely abnormal conditions with a minimum of risk to personnel

2- Enhanced Reliability:
The ability to maintain service continuity during abnormal system conditions

3- Enhanced Maintainability:
The system can be maintained with minimum interruption to service and with minimum personnel protective equipment.

4- Enhanced Flexibility:
The ability to add future loads to the system, and with loads of a different nature than currently exist on the system

5- Enhanced Space Economy:
The power system takes up the smallest possible physical space.

6- Enhanced Simplicity:
The power system is easy to understand and operate.

7- Reduced Cost:
The power system costs, both first cost and operating cost, are low.

8- Enhanced Power Quality:
The power system currents and voltages are sinusoidal, without large amounts of harmonics present. System voltage magnitudes do not change appreciably.

9- Enhanced Transparency:
The power system data at all levels is easily acquired and interpreted, and the power system is easily interfaced with other building systems. Enhanced control of the system is also possible.


in the next topic, we will see the types and electrical design Philosophy of Industrial Buildings. please keep following.

System Intertie transformers

Purpose of using System intertie transformers : 

 

fig (1) : System intertie transformers

System intertie transformer connect transmission systems with different voltages together with the purpose that active as well as reactive power can be exchanged between the systems

general Features of System intertie transformers :

• They have High power rating up to 1000 MVA. 
• The insulation of the windings is normally graded. 

Types of System intertie transformers :

1- Separate windings transformers: see fig.2

fig (2) : Separate windings , core type system intertie transformer

This type has separate windings for HV and LV levels as a normal transformer construction.

2- Auto-connected transformers (auto transformers): see fig.3

fig (3): 525 KV Auto transformer 

The system intertie transformers may be built as auto-connected windings to minimize Weight and physical dimension, to facilitate the transport from the factory to site, and to minimize the cost of making these transformers with separate windings.

The auto-connected transformer has two types as follows:

a- Common winding: which is connected to a neutral and as the name indicates, the turns of this winding are common for both sides of the transformer

b- Series winding: Which is connected at one end to the common winding and at the other end to the high voltage terminal.

Note:
The common winding and the series winding are arranged as concentric cylindrical shells, and the ampere-turns in the two windings are equal in value and opposite in direction.



System intertie transformers tapping: 

Tapping purpose:
The turns ratio of these transformers is fixed but when there is a need to increase the ability of reactive power exchange between different transmission systems, a tapping will be provided for these transformers.

Note:

In high voltages levels, the tappings may not noticeably influence the voltage on either side of the transformer).

Tappings location:
1- In separate windings transformers:

• tappings are placed in the neutral end of one of the windings 

2- In auto-connected transformers:

• tappings are typically located in the phases of the low voltage side (see fig.4).

fig (4)

• Sometimes, the tappings are located at the neutral point of auto-connected transformers (see fig.5) where the voltage level to earth and the voltage differences between phases are lower than when the tappings are situated at the auto tap. A simpler and cheaper tap changer can then be used. 

fig (5)

• On the other hand tappings at the neutral will need a larger number of turns in the tapping range to achieve the same variation in the turn ratio as when the tappings are situated at the auto tap or at the high voltage terminal. 

System intertie transformer special types:

there are important special types for System intertie transformers as follows :

• Phase- shifting transformers.

• HVDC transformers.

and in the next topic , i will show more information about these special types.

Conference Systems - Part One

Introduction: 

With domestic and international exchanges increase, in recent years, conference calls, video conferencing and digital conference system (DCN) has developed rapidly. Conferencing systems are widely used for conference centers, hotels, groups and government agencies. Conference system can be used as a conference discussion system, a voting system, a simultaneous interpretation system and a TV conference system.

 

But in this course we will focus on conference system as an Audio type system used as conference discussion systems and other types such as simultaneous interpretation system and a TV conference system will be explained later in other courses.


Conference Systems components: 

1- Input stage:

the input stage in conference systems include the following equipment:

• Microphones (wired or wireless) 
• Recording device 

For more information about Microphones, please follow the link.

2- Intermediate stage:

the intermediate stage in conference systems include the following equipment:

• Audio amplifier (boosters)
• Power supply
• Control unit: (see fig.1)Acting as the system hub it controls all aspects of the system using microprocessor technology. Intelligent functionality includes automatic speaker list, chairman priority, audio level control, remote controlling and more. 

fig (1):  Control Unit

3- Output stage: the output stage in conference systems include the following equipment: 

• Internal speakers 
• Loud speakers 
• Ceiling speakers 
• Recorders 

For more information about output stage speakers and how to select the right types among them, please review the following previous topic:

Speakers

4- Main equipment units:
Chairman unit:(see fig.2) it comes in (3) different types as follows:

 

fig (2):Chairman unit

1. It can be a typical delegate unit without any control to other delegate units. 
2. It can have a partially control to other delegate units with a priority button. 
3. It can have a full control to other delegate units with control panel having lot of permission keys.

Delegate units: (see fig.3) it comes in (2) different types as follows: 

fig (3):  Delegate units 

1. It contains microphone and talk button and in this case there is internal speakers in the conference hall.
2. It contains microphone, talk button and built in internal speakers and in this case speakers in the conference halls may be cancelled. 

Purpose of Audio Conference Systems:

The main usage for Audio conference system is providing a Direct Connection between Conference's Chairmen and the Conference's Delegates.

Audio Conference Systems types:

 Audio Conference System Is Divided into Three Main Systems according To the Method of Control of the direct Connection between chairman ans delegates as follows: 

1. Open Conference Systems.
2. Partially Open Conference Systems.
3. Controlled Conference Systems.

1- Open Conference Systems: 

This system is suitable for conferences with a limited number of delegate to speech each other without any control of the conference's chairman and it is ideal for small-to-medium-scale meeting areas, such as town halls, local business centers and courtrooms.

The sound system permits every delegate to speech to other delegates and chairman by switching on a talk button in his unit and talk through his microphone and if he wants to finish his speech, he will switch off the same button to switch off his speech circuit.



Types of open conference systems: 

1- without internal and External broadcasting:see fig.4

In This Case Delegate And Chairman Unit Contains Microphone , Talk Button and internal loud speakers.

fig (4)

2- with internal and External broadcasting:
In this type, the external broadcasting is provided by adding a remote loud speaker to different remote locations while the internal broadcasting is done by using one of the following methods: 

• The addition of Side Sound Columns in the conference Hall (see fig.5) and in this case  Delegate And Chairman Unit Contains only the Microphone and Talk Button.
• Or Providing the Delegates and Chairman Units with an Internal Speaker (Recommended) and In This Case Delegate and Chairman Unit will contain the Microphone and Talk Button and internal speaker. (see fig.6)

fig (5)

fig (6)

4-with U shape:  see fig.7

In this system we use a central power amplifier to connect the system with a remote microphone (which may be belong to the chairman and may be a wireless microphone) 

 

 

fig (7)

in the next topic, i will explain the other types for Audio conference systems. please , keep following.

Short Circuit Calculations Spreadsheets No.1

Siemens - Estimated Available Fault Current Calculation Spreadsheet 

 

 

1- Input data: 

the input Data for this Fault Current Calculations spreadsheet will be:

• Select the secondary voltage of used transformer.

• Sum the total horsepower of all motors on system (optional but recommended).

• Provide AIC (Ampere Interrupting Capacity) if the transformer is inside your system, or if the utility available current is known.

• Enter the primary voltage to the transformer if available (used only of you have provided a value for the available primary fault current).

• Enter the transformer rating in KVA.

 

• Input the nameplate transformer impedance as a percentage, not a decimal (i.e. 5.5% would be 5.5 not to be 0.055).

• OR If you have the available fault current, either given to you from utility, or if you are using this program to calculate fault currents at other parts of the system where the AIC (Ampere Interrupting Capacity) is known, input this number and it will automatically override the transformer based information. 

• Input the conductor length in feet (one way length).

• Select the conductor’s size.

• Select the conductor material (Aluminum or copper).

• Select the method of conductor’s installation (in conduit or in cable).

• Select the type of the used raceway/cable (steel or non-magnetic).

2- Output data:

the Output data from this Fault Current Calculations spreadsheet will be:

• The rated secondary current in Amperes 
• Available fault current 

Note: This spreadsheet estimates available fault currents for three phase systems. The calculation of motor contribution in this calculator is approximate only – systems with large motor contribution, high X/R conditions, and closed transition paralleled sources or high impedance grounding will require a more accurate calculation method.


if you want a copy from this Fault Current Calculations spreadsheet ,please click the following link:

Siemens - Estimated Available Fault Current Calculation Spreadsheet 

Note:

Non-registered members in Electrical-Knowhow website will not be able to open and use this excel spreadsheet.

To register as a member of Electrical-Knowhow website, do the following:

1. Click on the phrase “Follow" in bottom of the home page, below the images of our members.
2. After finishing your registration send email to ali1973hassan@yahoo.com, asking for your password and I will send it with email reply.

Coordination Drawings

Introduction: 

Coordination (sometimes called Composite) is critical to the success of any commercial or institutional building project today. Coordination in construction once referred to simply avoiding physical conflicts in the layout of equipment in spaces and the routing of duct, piping, and raceway systems through buildings. The risk of interference problems is highest on building projects that have intense mechanical, electrical, and plumbing (MEP) requirements. Production risks are compounded, as schedules become more intense. Eliminating coordination problems can be characterized as a prerequisite to the start of construction work on intense projects with dense MEP system requirements.


Coordination drawings definition: see fig.1

 

fig (1): Coordination (Composite) Drawing

Coordination drawings are Reproducible drawings showing work with horizontal and vertical dimensions to avoid interference with structural framing, ceilings, partitions, equipment, lights, mechanical, electrical, conveying systems, and other services:

• in and above ceilings. 
• within walls. 
• within chases. 
• in mechanical spaces. 
• in electrical spaces. 

Coordination drawings are mainly developed for sheet metal contractors, electrical contractors, mechanical contractors, and mechanical engineering consultants.



The purpose of coordination drawings: see fig.2

• The coordination process is performed to allow each trade to compare the materials that are intended for given spaces in a building to ensure they will not conflict physically, or impair the installation and maintenance of subsequent systems.

• Highlights plan discrepancies and missing/insufficient information provision. Allows contractors to effectively construct the project, with minimal time lost from the need to seek additional information or clarification from other parties. 

fig (3): Purposes of Coordination drawings

• Allow better estimation of cost & time in the schedule of works, and hence smoother workflow. 

• Frees up site staff to concentrate on more important key tasks instead of wasting time doing minor coordination tasks. 

• Reduce misunderstanding between the various parties involved in a project since everyone possesses the same development plans. 

Responsibility for issuing coordination drawings:see fig.3

• In current practice, Contractor/Subcontractors produce coordination drawings including plans and sections for structure & MEP works. 

• Such process is controlled and managed by a single coordinator in less complex projects or by coordination team in complex projects. 

• The coordinator / coordination team may be/include the Construction manager, the general contractor, design consultant or one of the construction team such as the HVAC contractor. 

• A final conclusion is that all project parties are participating in issuing and creation of coordination drawings. 

fig (3): Coordination drawings development team

Coordination drawing Creation procedures: see fig.4

• A single set of CAD drawings are developed for the space using electronic data files supplied by the consultant or developed by a member of the construction team from the construction contract documents. These CAD drawings would typically be three-dimensional for this purpose. 

• The coordination team decides as a group the assigned order in which the coordination work is to take place. The specialty contractors with building services that need to be fabricated and are sensitive to routing such as the HVAC air distribution system should start first. 

• The drawings pass from each specialty contractor to the next in the agreed to sequence. Each specialty contractor includes its work on the shared drawings. This can be accomplished by assigning each specialty contractor a specific CAD drawing layer. 

fig (4): Coordination drawings development Flow Chart

• If a specialty contractor encounters a conflict or problem with the work of a previous specialty contractor, the previous specialty contractor is contacted and the issue is resolved between them. If the two specialty contractors can’t resolve the conflict or problem then all of the specialty contractors working in the shared space should get involved to find a shared solution. If the group cannot resolve the conflict or problem, the General Contractor/Construction Manager should get involved along with the owner and/or design team where appropriate. 

• When the last specialty contractor has put its systems on the common drawings, it is assumed that all specialty contractors working in the shared space are in agreement and work can begin in the order dictated by the coordination drawings. 

• If there is a conflict during installation, the conflict is worked out between the specialty contractors with conflicting installations or the group as a whole. 

• Based on the coordinated installation plan, prepare a work plan that includes a schedule and sequence of work for the space. 

• Oversee the work as it is being performed to ensure that all specialty contractors adhere to the installation and work plans. 

• Prepare a record drawing for space as required by the construction agreement after the installation is complete. 

fig (5): Coordination drawings as 3D format

Note:
New technologies such as 3D and 4D modeling (see fig.5) promise to improve design coordination efforts by making design conflicts more visible to designers and construction planners. In isolated cases these technologies have yielded great benefit to users, but are currently perceived to be too costly for widespread use by building contractors.



In the next topic, I will explain another type of drawings which will be the record drawings.please, keep following.