Introduction

The 5 Key Characteristics of a High 

Quality Score Account

Theoretically there are a lot of factors that go into Google 

Quality Score. But the single most important factor is definitely 

normalized click-through rate (CTR).

We used the AdWords Performance Grader to get some high-level insight into what this 

advertiser is doing so right. Using this report, we identified five key characteristics that are 

contributing to the super-high average Quality Score of 8.8.

Amazing Click Through Rate

Theoretically there are a lot of factors that go into Google Quality Score. But the single most 

important factor is definitely normalized click-through rate (CTR). And this advertiser’s average 

CTR is off the charts:

That little yellow line represents the typical curve, with CTR plotted against average position. This 

account’s click-through rates are way, way higher than average — it’s got an average search CTR 

of 14.06% (2% is usually the benchmark for a decent PPC click-through rate). How did they get a 

14% CTR in an average ad position of 2.88?

Most of the outlier keywords with CTRs of 30%, 40%, 50% and even 70% are branded keywords, 

which generally have very high CTRs — but the rest of the keywords aren’t branded. In fact, 

it’s interesting to note that there are even 0% CTR keywords that have perfect Quality Scores 

of 10. This suggests that the high account average CTR is pulling up the Quality Scores for 

all keywords in the account. I see this in a lot of accounts, and it’s one reason why I always 

recommend slating at least 15% of your PPC budget toward branded keywords. But what about 

the rest of the keywords in this account?

1. 

 

Types of Stresses in Piping Systems

Primary, Secondary and Occasional Loads

From a piping stress analysis point of view the following are the main loads to be considered for the design

Primary load occurs from Sustained loads like dead weight, live weight, internal pressure etc. and are called non-self-limiting loads. Pressure thrust from an expansion joint is used in this article.

Secondary loads occur from thermal expansion loads like temperature change, anchors and restraints etc. and are called self-limiting loads. 

Thermal expansion in a horizontal pipe loop is used in this article.

Occasional loads occur from static wind and seismic loads and are considered to act occasionally. Seismic load on a vertical pipe loop is used in this article.

Primary Stress

Primary Stress is generated by internal and external force and moments. Primary stress is not self limiting – even if a part moves,the load causing it does not reduce. In this example, an expansion joint without restraining hardware creates a primary stress on a pipe.

Pipe loops with tied and untied expansion joints.The foreground joint is 

tied – it has tie rods to prevent axial growth of the expansion joint. The 

.background joint has no tie rods

Deflection of the two expansion joints under pressure. The tie rods limit the expansion of the tied joint. The untied joint increases in length the same as if it is a hydraulic cylinder applying bending stresses to the pipe

Pipe stress as reported by Caesar. The untied joint is applying a bending force, which, depending on the stress level, Caesar can report as a fail. 

This design does not meet the expansion joint manufacturers 

requirements for guiding and anchoring. The pipe with the tied joint is okay.

***This primary stress is caused by pressure of the fluid multiplied by the area of the pipe. It occurs all the time the system is pressurized. No matter how much the pipe displaces, the untied bellows keeps pushing on it

Because primary stresses are not relieved by the piping moving or yielding, primary stress limits are set lower than other allowable stresses. For example, if primary stresses managed to get above the yield point, the piping would balloon out and explode. The piping codes keep the primary stresses below the yield point by a factor of safety.

Secondary Stress *

Thermal expansion and contraction happens when a pipe heats up and 

cools down. The piping system must have enough flexibility to handle 

.the expansion

design piping system

 Introduction

Proper piping system design is critical for efficient movement of chilled or hot water in HVAC systems. Relevant codes and standards provide the basis for pipe design, but effective pump selection and pipe layout. depend on fluid dynamics and material selection. Designers incorporate several key aspects, from fluiddynamics to piping systems configuration Fluid dynamics focuses on how fluids move, considering both energy and momentum. The energy of a fluid is related to changes in elevation, temperatures, pressures and velocities, and directly impacts pump choice, placement and pipe layout. Momentum includes velocities, forces on pipes from fluid flow, and changes in pressure and flow from friction. Force, velocity and pressure are considerations in choosing pipe materials and design layout. 

Fluid Dynamics: Terms to Know

Flow rate and velocity are related. Velocity is the distance traveled over time (e.g., feet per minute, miles per hour). Flow rate is the volume of fluid over time as it passes through a point in the pipe (e.g., cubic feet per minute). Flow rate and velocity are used to size pipes and select pumps. Narrower pipes or restrictions in piping will increase the velocity. Flow pressure is the force the fluid needs to overcome resistance in the direction it is traveling. The pressure gradient from one point in the pipe to any other point in the pipe is what allows the fluid to flow. There is a relation between velocity and pressure. An increase in velocity decreases the pressure. Fluid pressure, which is different, is the force the fluid exerts perpendicular to the pipe wall. Wall thickness of pipes should easily resist this pressure. Friction is a force that resists motion between objects or substances. Sources of friction are the roughness of internal pipe surfaces, the length and diameter of pipe, and the fittings, valves and instruments that disrupt flow. Friction causes pressure drop and reduces velocity.

Some pipe characteristics to consider during the design process are friction factors, pipe wall thickness, and thermal and electrical conductivity. These characteristics directly impact pressure loss, heat loss to the environment, and durability. Material selection often depends on standards and codes, but where the design team has flexibility, it should carefully consider the characteristics and design elements that can either decrease negative impacts or take advantage of particular features

Pressure losses come from many sources. For example, fittings and valves, friction from rough pipe interiors, and bends in pipes all cause loss ofpressure within the pipe. The pressure difference between points before and after sources of pressure loss is the pressure drop. As the pressure drop changes, the flow characteristics change. System designs should provide adequate motive force from pumps so that the fluid makes it through the pipes. Different pipe materials will have different roughness coefficients or friction factors. Valves and fittings have equivalent factors.Pipe expansion requires balancing material choice and design. Pipe expansion is an unavoidable response of the pipe material when exposed to the temperature of the working fluid. Material characteristics determine how pronounced the response will be. Expansion and contraction distort the pipe’s girth and length. These changes stress the pipes, fittings and valves.Piping system designs can reduce the impact of expansion and contraction. Design elements, such as well-placed expansion loops, build flexibility into the system to accommodate the additional stresses. These design options introduce pressure losses, but it is a tradeoff that ensures the pipes last longer.

Special Concerns in Piping System Design

Design factors that contribute to corrosion and erosion inside pipes are elements that increase velocity or that cause turbulent flow. Except when necessary, avoid restrictions in piping and limit bends and elbows. In some cases, a design problem causes b.Both noise and damage. High velocity flow and sudden pressure changes not only increase damage to interior pipe surfaces or pumps, but they increase nois. 

Water hammer occurs with sudden pressure changes within a pipe, such as when a valve is quickly closed. This is more than a simple noise issue, however. The sudden pressure change creates a pressure wave that can damage pipes. Poor valve choice or operation is a common culprit. 

Sudden changes in pressure can also cause cavitation. Vapor forms in the pipe due to low pressure or very high velocities. Once the pressure increases above the fluid’s vapor pressure, the fluid rushes into the collapsing vapor bubble. This creates a small area of high pressure that can damage pipes and pumps.

Efficient HVAC systems are more than the best air handling units and chillers. Piping design is equally important. Fluid dynamics and material selection should work together for an efficient piping system.