1. Introduction

In accordance with the different norms and standards, the pipes must be selected in accordance with their class of nominal ring stiffness (SN), as SN2, SN4, SN8 or SN16 (in accordance with the standard ISO9969), or in accordance with any other stiffness standard (DIN 16961, ASTM F894, NBR 7373 etc.) notwithstanding the testing methods (at constant speed or constant load). For an example, a project requires pipe stiffness of 5.5 and the nearby standard value is that of pipe stiffness 8 and hence engineer could only provide details of profile with stiffness 8.

In addition to this and in accordance with article 9.1 of the standard EN 13476-3, the manufacturers are allowed to produce pipes that fall between the above listed SN-classes. To qualify for this admission the producer must be able to prove this solution with static calculations. With Krah pipes, are able to provide any project with pipes of the precise stiffness that the project demands.

It is useful to perform static calculations for pipes taking into consideration the specifications of each particular project. In 99% of cases the pipes selected for a particular project are over dimensioned in the original project design documentation. Using the calculations, it is possible to prove that it is sufficient to install a pipe with less stiffness but the correct profile, including the required safety factor which is also cost-efficient and faster to install.

The ATV A127, a German standard for static calculations for all kind of pipes is widely spread and used in the European region. It latest version dates from the year 2000. The software used by Krah was provided by IngSoft and is called Easypipe.

Globally, a different design manual is used for static calculations of flexible polyethylene pipes published by the American Water Works Association called M55 PE – pipe design and installation. Therefore, the Krah group developed a new software in Mickey for static calculations called structural pipe design according to AWWA M55. Static calculations according to AWWA M55 don’t need many parameters and information. It is user-friendly and easy to use.

The following chapters of this article will explain which input data is needed and which formulas are necessary to analyse, if a buried pipe verifies. 

These systems are mainly used to treat the surface water collected from the parking lots, air strips, road surfaces etc. The basic function of the light liquid separation systems is the liquid/liquid separation -  separating the light oil, petrol products to the surface water that is further sent for regular treatment. The separated and collected oil and petrol products are collected and treated separately. The quality requirements for the systems somewhat differ between regions, in Europe there is a specific standard EN858 covering the design and usage of these systems.

The European standard EN858 is governing the basics for the separator systems of light liquids. This standard covers the separation systems for light liquids (for example oil, petrol) with density below 0,95g/cm³. The standard itself is devided into two parts:

• Part 1 that covers the design, performance and testing requirements
• Part 2 that covers the selection of the nominal size, instalation, operation and maintenance related areas

I shall cover the types of the separators and their basic design in this brief report about the light liquid separation systems.

1 Introduction
For the static calculation of buried pipes, there are various regulations available on an international level. The publications of AWWA, SIA and DWA ([1] – formerly ATV-DVWK) are important for pipe statics. This article describes the basic procedure for the dimensioning of profiled pipes using the ATV-DVWK-A 127 (Germany) worksheet, as this set of rules also enjoys great international recognition.

2 Preface to the 3rd edition A127
"Due to new findings in pipe statics (experiments, comparisons with the finite element method, European standardization, etc.) and due to new developments in pipe systems (e.g. pipes with profiled walls), there is a need for regulation in various sections of the worksheet, which are summarized here in a third edition.

The mathematical limit between rigid and flexible behaviour is redefined with V_RB = 1. A new chapter is inserted for special features in the design of profiled pipes; a relevant data sheet ATV-M 127 Part 3 is in preparation". [2] p. 7. German edition translated.

Since 1989 the mass of insects in Europe has decreased up to 76%. It’s a topic which is constantly present, but nobody seems to take it serious and label it as a matter which is exaggerated by animal rights activists. Modern agriculture, climate change and habitat destruction lead to massive cuts in the number of Europe’s insects.
One third of the food we eat wouldn’t exist without bees. Honey, apples, berries, cocoa (chocolate), cotton, oils, creams, Make Up... just to name a few. This is the reality as it could be in 20, 30 or even 10 years.

 The factor we can influence the most is modern agriculture. The modern agriculture uses around 2.5 kilograms of pesticides per hectare of arable land per year. In sum that’s almost 40.000 tons in Germany per year. Pesticides, especially glyphosate or neonicotinoids, are mostly used in large companies which live from agriculture. They grow various fruit and vegetables and want them to look perfectly shaped and free of small insects like bugs or worms. To reach that they spray the fruit or vegetables with pesticides, so they can guarantee a perfect-looking, shiny end product, because that is what today’s society wants. And this is where the dilemma begins. The obvious pro of conventional agriculture is the output. While the biolo­gical agri­­culture reaches 75-87%, the con­ventional reaches 100%. Also, the price for biologically produced food is a little bit higher than “usual”. But what are these factors compared to clean, non-poisoned foods and animals living in much better conditions? Animals that aren’t fed with preventive medication and antibiotics (which we then take up), animals that can live free and aren’t squished together in a tiny stable with no sunlight or hygiene?
Additionally, as side effect, no insects or bees are attacked or poisoned with chemical plant protection products. But insect mortality isn’t the only problem we are facing if we keep on acting as if we had a Planet B. Most birds feed from insects and worms.

Accordingly, the number of birds has also decreased up to 50% in the past 30 years. Krah has decided to take a seemingly small, but effective step towards insect protection. For the past decades the lawns next to the company have been kept short due to optical reasons, but now we have seeded a large flower meadow. It has 3500 m² and has many different flowers for bees and insects to ensure a safe “resting place” and feeding station. If all of us would be a little bit more careful with our environment and would actually actively do something about it (e.g. taking care where and from whom we buy our food and thinking twice if we really have to mow all of our lawn with its flowers) we could eventually help the nature and animals to go back to a normal situation again.

                                                                                                                                                                 Jürgen and Lisa seeding the flower meadow

In the next issue of ImProfil we will hopefully be able to show how the meadow is growing and blooming.

Author:
Lisa, KAT GmbH