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LED Tube Light “Farm”

DLG-APPROVED "Resistance to ammonia, cleaning distance"

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The approval

A test mark „DLG-APPROVED for individual criteria“ is awarded for agricultural products which have successfully fulfilled a scope-reduced usability testing conducted by DLG according to independent and recognized evaluation criteria. The test is intended to highlight particular innovations and key criteria of the test object. The test may contain criteria from the DLG test scope for overall tests, or focus on other valuedetermining characteristics and properties of the test subject. The minimum requirements, test conditions and procedures as well as the evaluation bases of the test results will be specified in consultation with an expert group of DLG. They correspond to the recognized rules of technology, as well as scientific and agricultural knowledge and requirements. The successful testing is concluded with the publication of a test report, as well as the awarding of the test mark which is valid for five years from the date of awarding.

The ammonia resistance test was performed as a laboratory test according to the patented DLG test standard. This test is intended to determine the suitability of equipment for animal living areas to withstand the impacts of animal environments. The cleaning distance test assesses the suitability for cleaning animal living areas. Other criteria were not tested. As of 2017 the luminaires will be operated in the test chamber both passively (without power supply) as well as actively according to a determined test program.


Assessment – Brief Summary

The LED Tube Light “Farm” has successfully com­pleted the DLG test for ammonia resistance and cleaning distance. According to this result, it can be assumed that these luminaires are resistant to the typical environmental conditions of animal living areas and that no accelerated reduction of the product lifetime will occur. Furthermore, the cleaning distance is regarded as suitable for the cleaning of animal houses. In addition, the LED Tube Light “Farm” was operated actively in the chamber for the entirety of the test. No product damage was observed here.

Table 1: Overview of results

Test result Evaluation*
Resistance to ammonia of the luminaire housing  
resistant +
Cleaning distance  
Minimum distance with flat spray nozzel: 5 cm + +
Ingress of water into the housing without damages: No +

Evaluation scheme

Test result Evaluation*
Resistance to ammonia  
resistant +
partly resistant O
Ingress of water into the housing without damages  
no/yes + / –
Cleaning distance  
5 cm + +
10 cm +
15 cm O
20 cm
25 cm – –

* Evaluation range: ++ / + / ◯ / – (◯ = standard, n.a. = not evaluated)

The Product

Description and Technical Data

The tested LED Tube Light “Farm” is suitable for any usage in animal housing surroundings. Depending on the application, both borosilicate glass and PMMA are available as housing or diffusor material.

Table 2: Technical data (according to manufacturer)

The Method

Resistance to ammonia

The ammonia resistance of the LED Tube Light “Farm” was determined by a laboratory test with four luminaires according to the patented DLG test standard for agricultural use. The laboratory test is designed to replicate the conditions of a usage period of about 10 years exposure to animal living areas. The test was carried out in a climate chamber under the following climate conditions:

Test duration 1500 h
Air temperature 70 °C
Relative humidity 70  %
Ammonia concentration 750 ppm

For assessing the ammonia resistance, each luminaire was examined visually, gravimetrically and the plastic parts additionally through measurement of the hardness (Shore D) before and after the climate testing. Since 2017, luminaires have additionally been following a cycle of operation predefined by DLG (3 hours on, 1 hour off) in order to eveluate any thermal impacts caused by switch-on and -off procedures during ammonia fumigation.

In order to avoid overheating (> 70 °C), the luminaires could be operated at a reduced power level during the testing period.

Cleaning distance

During test bench examinations of the mechanical resistance to high-pressure cleaners, the minimum cleaning distance was determined. The minimum cleaning distance is defined as the distance between nozzle and surface when no damages can be observed at the housing surface. The test was conducted under the conditions presented in table 3.

Table 3: Test conditions cleaning distance

Line pressure ~150 bar
Water cold, approx. 1,000 l/h, no detergents
Nozzle type Flat spray nozzle, 25°
Exposition time 1 minute
Distance 250 mm, 200 mm, 150 mm, 100 mm, 50 mm
Ambient temperature 10°C

For all test procedures, the LED Tube Light “Farm” with PMMA and borosilicat glass housing material in
length of 685 mm and 1,530 mm has been used. After the tests, the luminaires underwent visual examination to a reference sample that was identical in construction.

The Test Results in Detail

Resistance to ammonia

Visual test

The comparative visual examination after the ammonia exposure has shown minor discolorations at the  luminaire housing and LED battens. However, no negative impact on the luminaire performance needs to be expected.

During the test, the tube light appeared to be sufficiently gas-tight. Nevertheless it cannot be ruled out, that a limited ammount of ammonium compounds could enter the luminaire housing. Again, no negative impact on the luminaire performance needs to be expected.

The defects are rated as insignificant. The examination of the manufacturer’s mounting parts didn’t also show any defects.

Gravimetric test

Weight comparisions before and after the ammonia fumigation have not shown any measurable increases
or decreases in weight.

Hardness test

During the hardness test (Shore D) no measurable changes were observed. All determined changes were within the measurement incertainty.

Based on the results of these tested parameters, the luminaire is evaluated as resistant to ammonia.
This applies to luminaires with PMMA-housing as well as to those with types equipped borosilicat glass housing.

Cleaning distance

Even at a cleaning distance of only 50 mm, no damages to the luminaire could be observed.
At no time a water ingress into the luminaires was noticed.

In order to avoid damage to the luminaires during cleaning reliably, according to the manufacturer’s speci­fications a minimum cleaning distance of 10 cm should always be ensured.

Functional test

No defects were observed. All luminaires worked after the conducted tests.


The results show that the LED Tube Light “Farm” fulfills the testing requirements for ammonia resistance and cleaning distance (evaluation “¡” or better) and thus receives the test mark DLG-Approved. It can be expected that the luminaire is resistant to ammonical air in animal living areas and that no accelerated reduction of the product lifetime occurs.

A cleaning distance at 5 cm is possible for that type of luminaire. It is rated to hold a distance of at least 10 cm. The LED Tube Light “Farm” was operated both passively and actively during the ammonia fumigation in the test chamber and passed both tests successfully. Other critera have not been assessed.

Applicant and Test implementation


Manufacturer and Applicant
SONLUX Lighting GmbH
Frankenhäuser Straße 66
99706 Sondershausen

Phone +49 (0)3632 6522-0
Fax +49 (0)3632 6522-822 

Test implementation

DLG e.V.,
Testzentrum Technik und Betriebsmittel,
Max-Eyth-Weg 1,
64823 Groß-Umstadt

The tests are carried out on behalf of the DLG by the DLG TestService GmbH as testing agency.

DLG test framework
DLG-Approved Test “Ammonia resistance”
(current as of 10/2017)


Head of Department
Dr. Ulrich Rubenschuh

Test engineer(s)
Dipl-Ing (FH) Tommy Pfeifer *

*    Author


DLG TestService GmbH - Groß-Umstadt location • Max-Eyth-Weg 1 64823 Groß-Umstadt Germany • Tel.: +49(0)69 24 788-611 •