Mechanical Practice Exam

MECHANICAL PRACTICE EXAM How to choose fire pump and what standard is required? - Water Supply, Suction and discharge pump, and auxiliary equipment / NFPA 20 Can you neglect the jockey pump and use two electric fire pump? - No What is the code used in Qatar? - Qatar Construction Specifications (QCS) What Class Class Class

are the types of fire hose reel? I - 65mm hose connection for Fire Department II - 40mm hose connection for trained personnel and Fire Department III - 40mm and 65mm hose connection for trained personnel and Fire Department

Light Hazard

Sprinkler system: Types - Wet Pipe Sprinkler Systems - Dry Pipe Sprinkler Systems - Deluge Sprinkler Systems - Preaction Sprinkler Systems - Combination Dry Pipe and Preaction Sprinkler Systems Area of coverage Light Hazard - 52000 ft2 / 4831 m2 Ordinary Hazard - 52000 ft2 / 4831 m2 Extra Hazard a. Pipe Schedule - 25000 ft2 / 2323 m2 b. Hydraulically Calculated - 40000 ft2 / 3716 m2 c. Storage - 40000 ft2 / 3716 m2 Protection Area/Spacing (Pendent / Upright) Amax = 21 m2 (any case) Noncombustible obstructed and unobstructed and combustible unobstructed

Pipe Schedule

Hydraulically Calc

Extra Hazard (All)

Combustible Obstructed (All) - 15.6 m2 / 4.6 m Combustible with members less than - 12.1 m2 / 4.6 m 3 ft on center (All) Ordinary Hazard (All) - 12.1 m2 / 4.6m Pipe Schedule - 8.4 m2 / 3.7 m Hydraulically Calculated - 9.3 m2 / 3.7 m (p >= 0.25) Hydraulically Calculated - 12.1 m2 / 4.6 m (p < 0.25) Distance below ceilings Distance from the wall

Unobstructed - 25.4 mm to 305 mm Obstructed - 25.4 mm to 152 mm Maximum - 1/2 L Minimum - 102 mm

Distance between sprinkler (A = S x L)

A - Area Covered by Sprinkler S - Distance between Sprinklers on the branch lines 4.6 m maximum for light hazard, 3.7 m for extra ha L - Distance between branch lines 4.6 m maximum for light hazard, 3.7 m for extra ha Sminimum - 1.8 m

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MECHANICAL PRACTICE EXAM No. of Branch Lines, NB = Width of Bay / Lmax How to test sprinkler and under what pressure - Refer to NFPA 25, 13.8 Bar for 2 Hrs

A lobby smoke detector shall be located in the ceiling within 6.4 m of the centerline of each el under control of the detector (NFPA 72_2013, Ch. 21.3.5) Flash rate of visible signals - Not more than 2 Hz nor less than 1 Hz

Time for technician or personnel to respond when alarm signals is received - 2 hrs

Alarm signals initiated by manual fire alarm box, automatic fire detedtors, waterflow from auto or actuation of other fire suppresion system(s) or equipment shall be treated as fire alarms. (N Digital signal Three types of signaling mode in fire alarm system Sprinkler Color Code Ceiling Temperature 38 oC 66 oC 107 oC 149 oC 191 oC 246 oC 329 oC NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA NFPA

Temperature Classification Ordinary Intermediate High Extra High Very Extra High Ultra High Ultra High

Color Code Uncolored or Black White Blue Red Green Orange Orange

Glass Bulb Color Orange or Red Yellow or Green Blue Purple Black Black Black

codes: 10 - Standard for Portable Fire Extinguishers 13 - Standard for the Installation of Sprinkler Systems 14 - Standard for the Installation of Standpipe and Hose Systems 15 - Standard for Water Spray Fixed Systems for Fire Protection 20 - Standard for the Installation Stationary Pumps for Fire Protection 22 - Standard for Water Tanks for Fire Protection 24 - Standard for the Installation of Private Fire Service Mains and their Appurtenances 25 - Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems 90A - Standard for the Installation of Air-Conditioning and Ventilating Systems 101 - Life Safety Code (Firestop / Fire Compartment) 204 - Standard for Smoke and Heat Venting 2001 - Standard on Clean Agent Fire Extinguishing Systems (FM200)

Pumps for Fire Protection Systems Q2/Q1 = N2/N1

H2/H1 = (N2/N1)2

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Hp2/Hp1 = (N2/N1)3

MECHANICAL PRACTICE EXAM Q2/Q1 = N2/N1 Jockey Pump Electric Fire Pump Diesel Pump

Hp2/Hp1 = (N2/N1)3

H2/H1 = (N2/N1)2

Cut in - 10 psi below system pressure Cut in - 5 psi below Jockey Pump cut in Cut in - 10 psi below Electric Fire Pump cut in

Frequency of Testing Audible and Visual (Fire Alarm Control Unit Trouble Signals) as per NFPA - Annually Frequency of Engine-Driven Generator as per NFPA 72 - Monthly Frequency of Testing of Heat Detectors as per NFPA 72 - Annually Frequency of Testing of Smoke Detectors as per NFPA 72 - Annually Frequency of Testing Initiating Devices, Supervisory as per NFPA 72 - Annually

Frequency of Testing Mechanical, Electrosonic, or Pressure-Type Waterflow Device as per NFPA - Semiannual Visual Inspection of Audible and Visible Appliances - Semiannual Frequency of Visual Inspection of Supervisory Signal Devices as per NFPA 72 - Quarterly Frequency of Visual inspection of Waterflow Devices as per NFPA 72 - Quarterly Frequency of Visual inspection of Smoke Detector as per NFPA 72 - Semiannual Frequency of Visual inspection of Heat Detectors as per NFPA 72 - Semiannual Frequency of Visual inspection of Duct Detectors, Manual Fire Alarm Box as per NFPA 72 - Semiannual What is a closed system Closed System (Thermodynamics)

Isolated System (Thermodynamics) Open System (Thermodynamics) Closed System (Classical Mechanics)

- No mass may be transferred in or out of the system bo always contains the same amount of matter, but heat exchanged across the boundary of the system. - Mass and energy remains constant within the system, transfer takes place across the boundary. - Matter may flow in and out of some segments of the s - A physical system which does not exchnage any matte and is not subject to any force whose source is extern

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MECHANICAL PRACTICE EXAM What is the specific speed of a gas turbine - Speed of turbine at max efficiency depends on head and flow N = nP1/2 H5/4

N - Specific Speed n - RPM P - Output power, HP H - Head of water in, ft

What is a differential gear used for? - Allow different tires to rotate on different speeds in a curved path - The differential gearing allows the outer drive wheel to rotate faster than the inner drive wheel during a t This is necessary when the vehicle turns, making the wheel that is travelling around the outside of the tu roll farther and faster than the other. What is 1 Ton of refrigeration? - The heat of fusion absorbed by melting 1 short ton (0.893 long ton; 0.907 t) of pure ice at 0 °C (32 °F) in 1 Short Ton = 2000 lbs / 907.18 kg 1 Long Ton = 2240 lbs / 1016.05 kg 1 Metric Ton = 2204.62 lbs / 1000 kg What is smoke test used for in HVAC? - HVAC duct leakage testing What is a deviation from specification is called? - Defect Deviation from Specification Out of Specification

- Is a planned on unplanned departure from the approved instruction during the process or before the process. - Should a material, product, or service fail to meet one or more of th specifications. - Is the result which is observed after the analysis in deviation from s which does not comes within the specified limit.

What is risk management strategy? - Mitigation - Is the identification, assessment, and prioritization of risks followed by coordinated and economical app resources to minimize, monitor, and control the probability and/or impact of unfortunate events or to ma realization of opportunities. Risk

- defined in ISO 31000 as the effect of uncertainty on objectives, whether positive or negative

What is the last estimate appears in a project? - Bid estimate ESTIMATE CLASS Class 5

NAME Order of Magnitude

PURPOSE Screening or Feasibility

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PROJECT DEFINATION LEVEL 0% to 2%

MECHANICAL PRACTICE EXAM Class 4

Intermediate

Concept Study or Feasibility

Class 3

Preliminary

Budget, Authorization, or 10% to 40% Control

Class 2

Substantive

Control or Bid/Tender

30% to 70%

Class 1

Definitive

Check Estimate or Bid/Tender

50% to 100%

1% to 15%

What is not a characteristics of a project? Project

- is a temporary endeavor designed to produce a unique product, service or result with a defi end (usually time-constrained, and often constrained by funding or deliverables), undertake goals and objectives, typically to bring about beneficial change or added value. - Is defined as a collaborative enterprise, involving research or design, that is carefully planne particular aim.

A thermal equilibrium changes from on state to another state. What is it called? - Process Thermal Equilibrium

- When two physical systems are brought into a connection that does not allow tr between them, and does not allow transfer of energy as work between them, s energy is transferred spontaneously between them, so that each changes state - Two systems are said to be in the relation of thermal equilibrium if they are linke permeable only to heat, and do not change over time. Zeroth Law of Thermodynamics - states that if two separate thermodynamic systems are each in the a third, then all three are in thermal equilibrium with each other. Molar Specific Heat of an ideal gas depends on? - Pressure Molar Heat Capacity

Specific HeatSubstances CPwater

- 4.185

- Is the heat capacity per unit amount (SI unit: mole) of a pure substance and the often simply called specific heat. J mol.oK - For liquids and gases, it is important to know the pressure to which given heat-c

- The specific heat capacities of substances comprising molecules (as distinct fro are not fixed constants and vary somewhat depending on temperature. J at 15oC, 101.325 kpa g . oK

What is morse test is used for? - Determining power of individual cylinder of an IC engine Definition of fire resistance material - Material designed to resist burning and withstand heat If a metal is heated, what happens to its strength and ductility? - Strength is reduced and ductility increased If insulation of pipe is increased, what happens to conduction and convection? - Both conduction and convection comes down

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MECHANICAL PRACTICE EXAM Thermal Conductivity - is the property of a material to conduct heat. It is evaluated primarily in terms for heat conduction. - Low thermal conductivity is equivalent to high insulating capability (R-value).

Definition of Bernoulli's equation - This states that, in a steady flow, the sum of all forms of mechanical energy in a fluid along a streamline all points on that streamline. This requires that the sum of kinetic energy and potential energy remain co - Derived from the principle of conservation of energy - Derived directly from Newton's 2nd law Definition of Buoyancy - is an upward force exerted by a fluid that opposes the weight of an immersed object. Definition of Equilibrium - When all the forces that act upon an object are balanced. Type of pump selection for high volume low head application - Axial flow pumps Radial Flow Pumps Mixed-Flow Pumps Velocity Pumps

- Operate at much higher pressure and lower flow rates than axial and mixed-flow - Operate at higher pressures than axial-flow pumps while delivering higher disch radial-flow pumps. - Centrifugal / Radial-Flow / Axial-Flow / Mixed-Flow/ Eductor-Jet Pump

Q1/Q2 = N1/N2

Q1/Q2 = (D1/D2)3

H1/H2 = (N1/N2)2

H1/H2 = (D1/D2)2

HP1/HP2 = (N1/N2)3

HP1/HP2 = (D1/D2)5

What is a manometer is used for? - Is an instrument that uses a column of liquid to measure pressure. h = Pa - Po gp

h - Fuid height in a liquid column Pa - Applied pressure Po - Reference Pressure

Sustainability development refers to - Development that meets the needs of the present without compromising the ability of future generations their own needs. - Development with minimum impact to environment, recycling and minimizing wastage.

Definition of Newtonian fluids - An element of a flowing fluid or gas will suffer forces from the surrounding fluid, including viscous stress f cause it to gradually deform over time. - If the viscous stresses that arise from its flow, at every point, are proportional to the local strain rate - the of change of its deformation over time. Which law of thermodynamics define entropy? - Third Law of Thermodynamics Zeroth Law First Law

- If two systems are in thermal equilibrium with a third system, they must be in thermal equiblibrium wih each other - Because energy is conserved, the internal energy of a system changes as heat

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MECHANICAL PRACTICE EXAM Second Law Third Law Entropy

- The change in the internal energy of a closed system is equal to the amount of system, minus the amount work done by the on its surroundings. - The entropy of an isolated system never decreases, because isolated systems a thermodynamic equilibrium, a state with maximum entropy. - The entropy of any pure substance in thermodynamic equilibrium approaches z as the temperature approaches zero. - A measure of the unavailable energy in a closed thermodynamic system that is measure of the system's disorder, that is a property of the system's state, and reversible change in heat in the system and inversely with the temperature of t - the degree of disorder or uncertainty in a system

What is the ideal location of an exhibition and convention center? -

What is Neutron Moderator used for in a Nuclear Reactor? - Is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable nuclear chain reaction involving uranium-235. NFPA code reference for a Car Park Ventilation - NFPA 88A Car Park Ventilation

- 300 L/min

= 1 ft3/min

m2

ft2

The sum of angles of six sided polygon - ∑Angles

= (n - 2) 180o = (6 - 2) 180o = 720o

Acceptable reasons for stopping a project -

An ethical question, what would you do if you find out after completing the project that somet Frequency of flashes of Fire Alarm Notification Appliances as per NFPA 72 - 1 to 2 hz Voice Appliances

- 520 Hz ± 10% with the appropriate harmonics

Re-inforced concrete used in the building structure Fast cooling effect of the welded point - Increase hardness and brittleness Excessive Low Cooling Rate

- The tensile strength and notch toughness of the weld decrease.

Pressure force direction for an emerged curved body - Downwards Management questions about planning -

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MECHANICAL PRACTICE EXAM

-Utilitarianism An ethical philosophy in which the happiness of the greatest number of people in the society is considere

Condensation of the water on a full cold water cup and relation with the dew point of the wate the wet/dry bulb temperature of the air

Dew Point - The temperature at which the water vapor in air at constant barometric pressure condenses rate at which it evaporates. - A high relative humidity indicates that the dew point is closer to the current air temperatur Dry Bulb - The temperature of air measured by a thermometer freely exposed to the air but shielded fro - The temperature that is usually thought of as air temperature, and it is the true thermodyna - It indicates the amount of heat in the air and it is directly proportional to the mean kinetic en Wet Bulb - The temperature of adiabatic saturation - This is the temperature indicated by a moistened thermometer bulb exposed to the air flow. Use of Fire Dampers - To prevent the spread of fire inside the ductwork through fire-resistance rated walls and floors.

Use Combination Fire Smoke Dampers - To prevent the spread of fire and smoke inside the ductwork through fire-resistance rated walls and floor

Use of Splitter Dampers Use of Volume Control Dampers -

Relation between Stress and Strain - Relationship between the stress and strain that a particular material displays is known as that particular m - These curves reveal many of the properties of a material (including data to establish the Modulus of Elast Strain Stress

= ∆L / L =F/A

Modulus of Elasticity

= (L2 - L1) / L1

- Is the mathematical description of an object or substance's tendency to be defo (i.e., non-permanently) when a force is applied to it. λ = Stress / Strain, Pa Young's Modulus, E

- Describes tensile elasticity, or the tendency of an obje opposing forces are applied along that axis - It is defined as the ratio of tensile stress to tensile stra - It is often referred to simply as the Elastic Modulus Shear Modulus, G or μ - Modulus of Rigidity - Describes an object's tendency to shear (the deformat when acted upon by opposing forces. - Defined as shear stress over shear strain Bulk Modulus, K - describes volumetric elasticity, or the tendency of an when uniformly loaded in all directions. - It is defined as volumetric stress over volumetric strai - Is the inverse of compressibility - The bulk modulus is an extension of Young's modulus

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MECHANICAL PRACTICE EXAM Decibel level for comfortable listening Conversational Speech at 1m Threshold of Hearing Hearing Range

- 20 micropascals, or 0.98 pW/m2 at 1 atmosphere and 25 °C, 0 dB - 20 Hz to 20 kHz (This corresponds to sound waves in air at 20°C with wavelengths of 17 meters to 1.7 cm / 56 ft to 0.7 inch).

If a metal is heated what happens to its strength & ductility - Strenght decrease and Ductility increase

Definition of Slack or Float - Is the amount of time that a task in a project network can be delayed without causing a delay to Free Floa Free Float

Total Float

- Subsequent Tasks, - The amount of time that a schedule activity can be delayed without delaying th or violating a schedule constraint. - Project Completion Date - The amount of time that a schedule activity can be delayed or extended from it without delaying the project finish date or violating a schedule constraint.

Schedule Performance Index, SPI - A measure of schedule efficiency express a the ratio of earned value to planned value - measures the success of project management to complete work on time. - measures relationship between the budgeted cost of work performed (BCWP) and the budgeted cost of w SPI = BCWP/BCWS SPI < 1 - less work was completed than planned SPI > 1 - more work was completed than planned

Cost Performance Index, CPI - measure of the cost efficiency of budgeted resources - measures relationship between the budgeted cost of work performed (BCWP) and the actual work perform CPI = BCWP/ACWP CPI < 1 - cost overrun for work completed CPI > 1 - cost underrun of performance to date

Critical Path Method, CPM - A method use to estimate the minimum project duration and determine the amount of scheduling flexibil paths within the schedule model. - Is an algorithm for scheduling a set of project activities Reynolds Number Re DH

Flow in Pipe:

- Reynolds Number - Hydraulic Diameter of the Pip

Re = ρvDH / µ = vDH / ν = QDH / νA

its characteristic travelled le µ v ν A

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-

Dynamic viscosity of the fluid mean velocity (m/s) Kinematic Viscosity (m2/s), ν Pipe cross sectional area (m2

MECHANICAL PRACTICE EXAM

Fast Tracking in a project. - A schedule compression technique in which activities or phases normally done are performed in parallel f a portion of their duration. Crashing

- A technique used to shorten the schedule duration for the least incremental cost by adding r

Fire Tank Material - Steel or Concrete Ventilation for Building or Rooms N = 60Q / Vspace

Q - CFM V - Volume of space, ft3

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L PRACTICE EXAM

Pipe Schedule

- 18.6 m2 / 4.6 m

Hydraulically Calculated - 20.9 m2 / 4.6 m - 15.6 m2 / 4.6 m - 12.1 m2 / 4.6 m - 8.4 m2 / 3.7 m - 9.3 m2 / 3.7 m - 12.1 m2 / 4.6 m

ween Sprinklers on the branch lines mum for light hazard, 3.7 m for extra hazard

mum for light hazard, 3.7 m for extra hazard

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L PRACTICE EXAM

n 6.4 m of the centerline of each elevator door within the elevator bank

fire detedtors, waterflow from automatic sprinkler systems, t shall be treated as fire alarms. (NFPA 72_2013, Ch. 26.3.8.1.2).

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L PRACTICE EXAM

Unit Trouble Signals) as per NFPA 72

Type Waterflow Device as per NFPA 72

e transferred in or out of the system boundaries. The system s the same amount of matter, but heat and work can be

gy remains constant within the system, and no energy or mass

w in and out of some segments of the system boundaries em which does not exchnage any matter on its surroundings, and ect to any force whose source is external to the system

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L PRACTICE EXAM

er than the inner drive wheel during a turn. s travelling around the outside of the turning curve

n; 0.907 t) of pure ice at 0 °C (32 °F) in 24 hours.

eparture from the approved instruction which is observed

or service fail to meet one or more of the applicable

ed after the analysis in deviation from specification

ed by coordinated and economical application of impact of unfortunate events or to maximize the

bjectives, whether positive or negative

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L PRACTICE EXAM

e product, service or result with a defined beginning and by funding or deliverables), undertaken to meet unique

earch or design, that is carefully planned to achieve a

nto a connection that does not allow transfer of matter fer of energy as work between them, still it can happen that ween them, so that each changes state. n of thermal equilibrium if they are linked by a wall

hermodynamic systems are each in thermal equilibrium with thermal equilibrium with each other.

unit: mole) of a pure substance and the specific heat capacity,

now the pressure to which given heat-capacity data refer

s comprising molecules (as distinct from monatomic gases)

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L PRACTICE EXAM

eat. It is evaluated primarily in terms of Fourier's Law high insulating capability (R-value).

al energy in a fluid along a streamline is the same at energy and potential energy remain constant

wer flow rates than axial and mixed-flow pumps ow pumps while delivering higher discharges than

mising the ability of future generations to meet

ounding fluid, including viscous stress force that

proportional to the local strain rate - the rate of change

al energy of a system changes as heat flows in or out of it

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L PRACTICE EXAM

osed system is equal to the amount of heat supplied to the

decreases, because isolated systems alaways evolve toward

rmodynamic equilibrium approaches zero

closed thermodynamic system that is also usually considered to be a s a property of the system's state, and that varies directly with any and inversely with the temperature of the system.

ng them into thermal neutrons capable of sustaining a

completing the project that something was not done as per specified?

ch toughness of the weld decrease.

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L PRACTICE EXAM

er of people in the society is considered the greatest good

ion with the dew point of the water in the surrounding air and

onstant barometric pressure condenses into liquid water at the same

is closer to the current air temperature. reely exposed to the air but shielded from radiation and moisture. perature, and it is the true thermodynamic temperature. ctly proportional to the mean kinetic energy of the air molecules.

rmometer bulb exposed to the air flow.

ugh fire-resistance rated walls and floors.

al displays is known as that particular material's Stress-Strain curve g data to establish the Modulus of Elasticity, E)

ect or substance's tendency to be deformed elastically

le elasticity, or the tendency of an object to deform along an axis when

the ratio of tensile stress to tensile strain ed to simply as the Elastic Modulus.

bject's tendency to shear (the deformation of shape at constant volume)

metric elasticity, or the tendency of an object to deform in all directions

volumetric stress over volumetric strain

us is an extension of Young's modulus to three dimensions

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L PRACTICE EXAM

W/m2 at 1 atmosphere and 25 °C, 0 dB ponds to sound waves in air at 20°C

yed without causing a delay to Free Float and Total Float.

vity can be delayed without delaying the start date of any succesor

vity can be delayed or extended from its early start start date without

med (BCWP) and the budgeted cost of work schedule (BCWS) as a ratio

med (BCWP) and the actual work performed (ACWP) as a ratio

mine the amount of scheduling flexibility on the logical netwrok

- Hydraulic Diameter of the Pipe; its characteristic travelled length, L (m) - Dynamic viscosity of the fluid (Pa-s or N-s/m2 or kg/m-s) - Kinematic Viscosity (m2/s), ν = µ/ρ - Pipe cross sectional area (m2), πD2/4

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L PRACTICE EXAM

rmally done are performed in parallel for at least

r the least incremental cost by adding resources.

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