Based on a new thread discussed here (Number of gallons/Litres) may be there is the need to discuss “deeper” EHS-BD/EHS-PS/EHS-GLM/EHS-DG and some challenges in WWI. The main challenge in context if the thread is the “correct” use of “UoM”s in EHS. The use of UoM is a “science” (for some people) in SAP at all(
I believe If I would start in inquiry in the SAP SD/MM etc. world I would get quite interesting feedback about the use of “UoM”) and especially in context of EHS there are a lof of challenges to handle the proper use of “UoM”s.
Quite interesting is the use of “UoM” in context of SAP services (e.g. check SAP EH&S Regulatory Content and SAP Unit of Measures (UoM) are definied different ).
What are the challenges in context of “UoM” in EHS-BD and what are the effect on processes and IT design?
Based on the above mentione thread: the main intention of EHS-BD (Basic Data and Tools (EHS-BD) – SAP Library) is:
- Enter data
- Use output variants to check data
- Use Rulesets etc. to enhance data
- Use e.g. OCC to upload data
- and to use CG02/CG02BD as “inquiry” tools for product safety etc. information
But the data entered should be used in many subsequent processes as well. Examples are:
- Generate e.g SDS/MSDS (or other WWI reports)
- Support Dangerous Goods topics
- Support Hazardous Substance topics
- Support labeling topics
- Support SVT
Especially for companies acting “international” the tool should be useful with many languages (e.g. either as “log on languages” or langugages which are supported in context of phrases/identifiers etc. as well as WWI reports etc.)
Some kind of information maintained in EHS-BD contains a relation to a “UoM” (Unit of Measurement). Sometimes this relation is underestimated.
Data maintenance in EHS-BD
Data having a relation to a “UoM” is maintained in:
- properties/value assignment types which do have a SAP EHS Class assigned (Value Assignment Category Property – Basic Data and Tools (EHS-BD) – SAP Library)
- properties/value assignment types which dare of Type “C” (Composition) (Value Assignment Category Composition – Basic Data and Tools (EHS-BD) – SAP Library)
EHS-BD contains some nice mechanism to deal especially with characteristic having a “UoM” relation. This is explained here: Conversion of Units of Measurement – Specification Management (EHS-BD-SPE) – SAP Library
Especially the use of the “right” UoMs can be a challenge in context to “composition” e.g. to support cascading, execution of rulesets etc.
As well during an “inquiry” for a characteristic data having “UoM” relation the “UoM” topic is supported in SAP EHS. That means you can enter a temperature e.g. 20 °C and the system will generate any hit list using this input and internally doing the conversion (that means: if there is a data record havin value e.g. 293 K (20°C = 293 K) you will get a hit as well)). As well the same mechanism is used internally if you execute e.g. rule sets.
EHS classic set up/class/characteristic set up
Please check these quite interesting threads:
The discussion running there is very interesting. Only a subpart of the discussion should be discussed here:
A property tree is a collection of value assignment types. It can be assigned to a specification type and can then be used in daily maintenance to simplify the topic. The property tree contains at least one node (the root node) and one or more value assignment types. Here you can use, if needed, subnodes to “organize” the data. Using the EHS data model you can maintain the data and then “reference” to this data and ýou can as well “inherit” it. But you can do that only for the whole “value assigment instance”. Especially the “interitance” can be an interesting feature to use (but quite complex)
Value Assignment types
All of the “properties” as part of a property tree are defined using a value assignment type. Here you can use e.g. value assignment types having a reference to a class of class type 100. A class can contain one to X characteristics which can be used to split the data to be maintained in more “smaller” pieces (and in most cases this is needed to “align” the data).
Example: State of Matter. E.g. looking on the very simple example “water” this is true: for a pressure of 1 bar water is solid <= 0 °C, it is liquid between => 0 and <= 100 °C and a gas/vapour above 100°C; those who are climbing know that as higher you come as lower the pressure. Therefore this has as well effect on the temperature at which water is solid, liquid or a gas. Conclusion: from chemistry point of view: you must specify temperature and pressure at the same time to specify if water is solid etc. Especially on the area of “tox” and other properties you may have more variables which have an impact on the result.
If you are not satisfied with the SAP EHS data model you have these options:
a.) use e.g. UserDefined text to add more information; here you can add as many user defined text types you would like to use; there is no limit; this is allowed in SAP
b.) define your own value assignment type + class/characteristic of e.g. type “density” and add additional characteristics
It is strictly recommended not to mix SAP classes or SAP characteristics with your own ones !
Coming back now to the “UOM” discussion in the one thread. UOMs are not belonging to EHS set up. Like countries, currencies etc. they are belonging to “basic set up of SAP ERP”. Especially UOMs are the “worst” thing to customize. You should be at least an advanded not to say expert or super expert in setting up UOM to really understand what you can do and what you have to avoid, For one numeric characteristic you can only assign one UOM type; any UOM which has the same “type” can be then used in the characteristic. Example: you can maintain temperture as “K”, “°C”, “F” etc. All these “dimensions” can be converted to each other. The same is true for density. Here you can use: kg/m3, g/ml etc. etc. Anything which belongs to a dimension of type “mass/volume” can be used if the customizing is done properly. Therefore: if you check “tox” and other properties you will realize that sometimes more than one characteristic is there to be used to specify some value; but you can not convert the UOMs of the both to each other. And you will find as well some characteristic there no “real UOM” is available any more. E.g. the legislation is saying sometimes: number of fibres / volume, fibres/area etc. in this case SAP has decided: no chance to find “suitable” UOM and generated two characteristrics. One for the value and the second is used as a phrase based one to deal with the UOM. Legislation can be really complex here
For some of the characteristic you will find as well special WWI methods to “convert” the values “on the fly” from database to a valeu in WWI report.
Use of data in EHS-DG
Data maintained in EHS-BD should be used as well for Dangerous Goods perspectives. Quite nice mechanisms are delivered by SAP to generate the data in EHS-DG; there is only one “but” in most cases the data is retrieved “as is” with out a conversion. As e.g. flash point, denisity etc. are part of Dangerous Goods Master you may ask yourself: in which “UoM” should be the value to be used? E.g. may by after some inquiry you might have the feeling e.g for US regulation it might be better to use “Fahrenheit”. Now you have two options. Option 1 is the “easist” one. Just prepare use ful data record in EHS-BD using “Fahrenheit”. But this would lead to the question of “maintenance” rules. Therefore sometimes only data in “°C” is available. Sometimes you would like to avoid to maintain a second data record in “Fahrenheit” in parallel to “°C” value. Now you can “easily” enhance DG filling process to consider this. But may be the users need to be trained more (as in EHS-BD you might find “°C” and in corresponding EHS-DG you might find “Fahrenheit” and sometimes it is not easy to explain why.
Use of UOM related data in WWI
For WWI reports the story is nearly the same. In most cases: what you maintain you will get in WWI report. But as with DG topic. Sometimes you would like to maintain “simple” but print “Fahrenheit”. Here you have no other chance as to generate a customer symbol (or to manipulate SAP symbol). So that the value is retrived from data base and if needed converted to “Fahrenheit” to be printed
EHS is quite flexible in using “UoM” but sometimes you need either “maintenance guidelines” (leading to more data in database) sometimes you are willing to “extend/enhance” SAP EHS functionality to show the “UoM” in WWI reports as wished (which lead to add on IT efforts). A very special topic is the handling of “UoM” in compostions. As there is no thread which I know in this FORUM discussing “UoM” handling in context Composition I will not explain the topics which might come up (if you do not use it properly).
E.g. check: WWI for Experts