Blog posts tagged with 'expert tips'

As we work not only with large companies but also a smaller ones and even individuals, we are often asked about whether someone can or cannot set out their own housing development. Today we want to answer that question and explain what you need in order to tackle such a task.

Can I set out my housing development?

The short answer is yes, you can indeed set out your own house, if you feel up to the task.

In order to do that, though, you'll need four fundamentals:

• AutoCAD,
• georeferenced AutoCAD drawing (including legal boundaries, house coordinates and roadways),
• setting out equipment,
• and finally - knowledge and training on said equipment.

Let's take a closer look at each of these elements.

AutoCAD

So what exactly is AutoCAD?

AutoCAD is a computer-aided design software developed by the company Autodesk (hence the name AutoCAD). It allows you to draw and edit digital 2D and 3D designs more quickly and easily than you could by hand. The files can be saved and stored on your computer or in the cloud, so they can be accessed from anywhere at any time. 

AutoCAD file format is either in DXF (.dxf) or DWG (.dwg). 

AutoCAD was once an expensive package bought in a particular year, AutoCAD 2013 for example. Retailing at around €2,500 you bought it with the intent of updating in 5 years, which was not feasible for some small companies with only one user.

Annual subscriptions have improved this. Now you can buy the latest every year for a 1/5 of the price and always have the latest, most up to date version, meaning there is no issues with i.e. opening a file due to incompatibility.

Using AutoCAD in Hitechniques, we can point you in the right direction and guide you to the right place.

Georeferenced drawing

Before I explain what coordinated drawing is, let's go back to basics and talk about what coordinates are.

Coordinates are the numbers describing the position of the particular point on the map. There are 2 coordinates - Easting and Northing. Sometimes, when the level is important, they are followed by a third coordinate - Height. Easting coordinates are listed first followed by Northing - Easy way to remember is it’s in alphabetical order (ENZ). Coordinates are described by the coordinates system.

Generally, there are 2 coordinates systems in use in Ireland.

1. IG (Irish Grid or National Grid), superseded in 2001 by
2. ITM (Irish Transverse Mercator)

The official system is Irish Transverse Mercator (ITM) which is our local coordinates starting at point 500000,500000 off the coast of Kerry and increasing in increments of 1 m northerly and easterly and every millimetre in between. ITM is more compatible with satellite positioning used for precise surveying and minimise mapping distortions. (https://www.osi.ie/wp-content/uploads/2015/07/Survey-Ireland-2007-ITM-Tutorial1.pdf)

Figure 1: Irish Grid Coordinates

Source: Wikipedia

Some local authorities still use Irish Grid system, however it hasn’t been recommended by Ordnance Survey Ireland since 2001 (Gas Networks Ireland, some local offices of Irish Water, County Councils). 

Figure 2: Irish ITM Coordinates

Source: Wikipedia

What if you have a house drawing but don't know ow to put it on site layout?

A digital map or AutoCAD survey of the site needs to be acquired either through past surveys or purchased online. A site layout of all the units and roadways, footpaths and car parking bays, etc. will need to be considered, when adjusting the position of the house layout. Ideally this should be done by the professional.

How do you get a georeferenced drawing?

Research into the site development and professionals involved, will have surveys from past projects or planning applications and these are going to be more detailed and more accurate

Digital Maps can be purchased online from https://www.osi.ie/products/professional-mapping/

These maps are sometimes not that accurate but give a good indication of site boundaries and surround lands and roadways. Accuracy of these can be sometimes up to 1.5m out of position and must always be checked and referenced. Again, ask a professional for help if needed).

Setting out equipment

Now that you have your coordinated drawing ready, it's time to do the actual setting out. 

You can be tempted to do the setting out using one of the simple, traditional methods but we strongly encourage you to invest in a modern survey equipment and software. Accurate setting out is a fundamental part of the construction works, and errors can be very expensive and time consuming to correct.

When your equipment is ready, your drawing can be uploaded to a portable data logger and then with the help of GNSS rover or a total station, you can precisely set out your design using marking stakes, flags or nails depending on your site.

Surveying training

Modern surveying instruments and software are designed with the end user in mind, so there is a lot of pressure on making them as easy-to-use as possible. Once you have a general idea on how things work and some hands-on training you should be able to perform a simple survey or set out a building without any issues.

If you'd like to start using GNSS rover or a total station but have no previous experience, you can sign up for one of our surveying training courses. They're designed with beginners in mind and are a great way to get into the world of construction surveying. 

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Need help choosing the right instrument for you? Get in touch with us to schedule a consultation and/or a free demo on your chosen unit. Call 01 257 2323 or email info@hitechniques.ie

What is a pipe laser and how does it work?

A pipe laser is a type of construction laser that is used to measure and determine the correct grade for pipes. It makes grade calculations in sewer, wastewater and other linear pipe runs a lot easier. 

Pipe lasers provide ease of operation and computerized self-calibration that can speed pipe laying. They directly determine your pipe grade and help you to handle all the tricks and exceptions that arise when you are installing sewer pipe and other lines. 

Pipe lasers shoot a high-powered beam of light at a predetermined angle to establish the appropriate grade of a construction project. Standard pipe grade setting involves determining the length of pipe, the depth to the invert and details such as any protrusion into manholes. Ensuring you have accurate and appropriate numbers, you can calculate the change in depth of the pipe invert over the length of the pipe and derive a grade percentage from that.

How to calculate pipe laser reading?

A pipe grade is the incline or decline at which a pipe is set, and is expressed as a percentage. The grade of the pipe helps manage liquid flow in underground construction projects. This percentage is calculated by dividing the elevation difference by the run of pipe.

If the gradient between the manholes is given in rise/fall or as a ratio, calculate the laser reading as follows:

Things to remember:

1. If the rise/ratio is given as 1 in 85 make sure that both dimensions are the same

e.g.  1” in 240” NOT 1” in20’

        0.150m in 30m NOT 150mm in 30m 

        150mm in 3000mm NOT 150mm in 30m

2. + grades always RISE away from the laser

    - grades always FALL away from the laser

3. When using the LASER CONVERSION CHART read the Rise/Ratio (e.g. 1:85) from the LEFT hand column and the corresponding Pipe Laser Reading (1.176) from the RIGHT hand column.

Potential outside sources of error

• During pipe laying, logging in the pipe may be encountered leading to refraction of the laser beam. Since the beam appears to drift, the operator is likely to think that something is wrong with the instrument. This refraction problem can be solved by placing a fan at one end of the pipe to keep it clear.
• Retraction caused by heat and particles in the air can also be a problem when using a rotating laser beam, especially at extended distances. To give you an example, a reading error of up to 6mm can be caused by refraction and the curvature of the earth at as little as 300 meters range.
• Reflections can result in incorrect signals to the laser detector. Glass-walled buildings can cause such reflections. This problem can be prevented by shielding the building from the beam with a blind mounted on the instrument.
• Other factors which can affect the laser beam are heavy rain, fog or snowfall - water and ice particles in the air can lead to incorrect readings. 

Pipe lasers can make a huge difference in overall cost project by saving time and ensuring highest accuracy.

Pipe lasers are designed to help with specific pipe installation challenges, including long linear runs of supply or waste pipe. They don’t eliminate the need for skilled personnel to ensure that the overall installation is true and correct, but they can make a large difference in overall project costs and accuracy and can let pipe installation personnel perform their own measurements easily on smaller projects.

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Download our handy Laser Conversion Chart.

Hire pipe laser at a great rate from our Hire Shop.

If you are working within or with the underground utilities sector or are, at any point, breaking ground, you must ensure that adequate precautions are taken to avoid risk to persons at work arising from possible underground dangers such as underground cables. Using the right cable avoidance tools (CATs) will ensure the safety of your team and help you avoid costly damage and delays.

So how do you pick the right cable avoidance tools?

With so many different brands offering range of products, it’s hard to decide which is the best for you and your budget. Before you make a purchase there are a few questions you need to ask yourself. 

1. What kind of accuracy do you need?

You need to consider your application and think of distances over which you would ideally like to trace. Wat about the depth of the services? Do you need to be able to measure that as well?

Average cable locator will provide you with the lateral position of any services detected and used with a signal generator can operate using the two industry-standard detection frequencies of 8khz and 33khz.

But if you need something more advanced, there are models that can emit two additional frequencies and detect signals over longer distances. They are also able to provide a depth reading.

2. Will you be using the CAT in isolation or with a signal generator?

Best practice requires you to always use a cable avoidance tool in contact with a signal generator. It doesn’t mean you have to but using a Genny will help you find about 50% buried services, since CAT can only detect a cable if it has current flowing through it.

Note: It is very important that you always use the correct signal generator and cable avoidance tool combination.

3. Are you just marking-up services on the ground or do you need to store that data for later analysis?

Any basic tool will do if you’re just marking the ground for a surveyor who will do the mapping or to avoid cutting a wire. But if you need to be able to record data yourself, you may want to look at more advance models, like the ones with the GNSS technology and software included.

4. How experienced are you/your employees in using these tools?

You don’t need to be an expert to use cable detection tools, however having a basic understanding of how they work is necessary for you to use a utility locator correctly. If you don’t have much experience, it’s often best to start with a simple tool and get familiar with it, before upgrading to more advanced one. No point spending money on something you won’t be able to use.

Conclusions and recomendations

As industry standards get more and more regulated, it makes sense to buy the best and most recent cable and pipe location technology. Still, it’s important to take under consideration all the above factors. You need to make sure to pick the tool that ensures safety but also fits your needs and budget.

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At Hitechniques we offer a range of detection tools for every job and budget. If you need help picking the right ones for you, get in touch with us at 01 257 2323 or info@hitechniques.ie

There is a lot of measurement equipment available on the market for construction companies and surveyors. You can pick from hundreds of different models and, whatever your requirements, you'll always find one that will suit your needs perfectly. However, buying tools like GNSS Rovers or total stations is a big investment, especially for individuals and small companies.

When basing your budget on a lower scale, purchasing a second-hand unit from an authorised dealer can be a great option. You can save a lot of money and still get quality instruments that are fully serviced and certified. It usually comes with original packaging and with all the accessories included. Warranty is also something that most authorised dealers offer when selling used instruments. But before you take that leap of faith and buy pre-owned instrument, there are a few matters to think about.

Five things to consider before buying used surveying equipment

1. Cost

There is no doubt that you can save a lot of money buying used equipment and since survey equipment is considered business equipment you can write it off as an expense to your company.

2. Type of equipment you need

Consider all the features and functions that are necessary for your work. If you’re only starting in the business maybe less expensive, pre-owned units will be a better practice tool? Or maybe you just don’t really need the latest technology and don’t feel like paying extra for something you don’t have use for.

3. Frequency of use 

If you need the instrument on daily basis but can’t afford a new one, buying used is definitely worth considering. However, if surveying work is more one-off type work, it may be worthwhile hiring instead.

4. Warranty and support 

Always check what kind of warranty you will get, when buying second hand and if you’re entitled to the same support services as customers buying new tools.

5. Available payment options 

Some companies offer payment plans. If you don’t have the cash, it can be a great help, too. 

Buying pre-owned surveying equipment can be a great way to upgrade while saving money as long as you make a well educated decision. Don't be afraid to ask questions and check the instrument you want to buy before commiting. It's still a great investment and you want to make sure you get your money's worth.

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If you’re considering buying used surveying or construction equipment, get in touch with us. Whatever your budget, we can help find the right instrument for you.We will help you choose the kit and software according to your experience and the type of projects you work on. And if needed, we also offer a training service to help you get familiar with the new instrument.

Give us a call at 01 257 2323 or email us at info@hitechniques.ie