Safety recom­mend­a­tions


1.1 Poten­tial danger
Work­ing with high pres­sures does­n’t have to be dan­ger­ous.
The pres­sure / liter product, i.e. the product of volume and pres­sure, is decis­ive for the poten­tial risk of a pres­sure-bear­ing sys­tem. In addi­tion, how­ever, there is the com­press­ib­il­ity of the flu­id and the expan­sion of the pres­sure body and the dan­ger­ous­ness of the flu­id — (flam­mable, caustic, pois­on­ous). All gases and liquids are flu­ids.
Often the prob­lems, espe­cially with gas sys­tems, tend to occur in the low-pres­sure range, since too little atten­tion is often paid to this. Gas cyl­in­ders, for example, are often a great­er source of danger than high pres­sure sys­tems.
The dangers of a high pres­sure sys­tem are some­times mis­judged. Safety devices are installed out of place, are too weak or vice versa, or are cre­ated with excess­ive effort.
To ensure oper­a­tion­al safety, always make sure that the sys­tem is in good con­di­tion and that reg­u­lar tests are car­ried out.

1.2 Advice
People work­ing with a high pres­sure sys­tem must be aware of the dangers that can arise. If in doubt, con­sult a spe­cial­ist. Obtain writ­ten noti­fic­a­tion of which secur­ity meas­ures he deems appro­pri­ate. When select­ing the com­pon­ents, it should be ensured that they have the neces­sary capa­city, pres­sure approv­al, cor­ro­sion res­ist­ance and oth­er required func­tions so that they can be used for the inten­ded pur­pose. We would be happy to advise you on the selec­tion of the com­pon­ents, but the final decision and the respons­ib­il­ity to ful­fill the task to the sat­is­fac­tion rests with the user.
You can also call in a com­pet­ent expert at any time, even if there is no oblig­a­tion to accept the sys­tem. In Ger­many, experts for pres­sure ves­sels are Dekra, TÜV or DNV-GL.
For each lar­ger high-pres­sure sys­tem or sev­er­al togeth­er, there should be a safety officer who famil­i­ar­izes him­self with the mat­ter and who is appro­pri­ately trained through appro­pri­ate courses and courses. The employ­ees work­ing with a high-pres­sure sys­tem should be informed at reg­u­lar inter­vals, e.g. every three months, about the applic­able acci­dent pre­ven­tion reg­u­la­tions and neces­sary safety and pos­sibly also first aid meas­ures. Any “near misses” should also be dis­cussed. The safety officer should reg­u­larly check that the employ­ees are fol­low­ing all safety instruc­tions and that the neces­sary safety checks are car­ried out in accord­ance with the regulations.

1.3 Man­u­fac­ture of plants
High-pres­sure sys­tems may only be man­u­fac­tured by com­pet­ent spe­cial­ists.
If you do not belong to this group of people, obtain a com­plete, prop­erly man­u­fac­tured sys­tem with the asso­ci­ated accept­ance papers and safety devices.
Every print­ing sys­tem must com­ply with the Pres­sure Equip­ment Dir­ect­ive and / or the Machine Pro­tec­tion Act. Just as it is not per­mit­ted to drive an unau­thor­ized motor vehicle, it is not per­mit­ted to work with an unap­proved high-pres­sure sys­tem.
The Machinery Dir­ect­ive can be read under the fol­low­ing link:
Com­pli­ance with the Machinery Dir­ect­ive is required by law. The Machinery Dir­ect­ive is quite extens­ive, essen­tial parts are a mat­ter of course for a machine man­u­fac­turer. It makes more sense to observe the Pres­sure Equip­ment Dir­ect­ive, which is part of the Machinery Dir­ect­ive.
The Pres­sure Equip­ment Dir­ect­ive can be found under the fol­low­ing link:

1.4 ener­gies under pres­sure
Nev­er under­es­tim­ate the ener­gies of a flu­id under pres­sure. The com­press­ib­il­ity of water at 1,000 bar pres­sure is approx. 5%, that of oil approx. 10%. In addi­tion, there is the elast­ic ten­sion energy of the com­pon­ent and pos­sibly the chem­ic­al energy of the con­tent. These forces are sud­denly released. You can greatly accel­er­ate a com­pon­ent and provide it with con­sid­er­able pen­et­rat­ing power.
A pos­sibly escap­ing liquid jet can lead to ser­i­ous injur­ies, includ­ing cut­ting off parts of the body. A jet of liquid pen­et­rat­ing the body tis­sue usu­ally leads to blood pois­on­ing and must be treated imme­di­ately.
Gas sys­tems are more dan­ger­ous than liquid sys­tems, because
they accel­er­ate any released com­pon­ents more strongly in the range below 1000 bar. When the gas has reached its own volume dur­ing com­pres­sion, from around 1000 bar, the dif­fer­ence in com­press­ib­il­ity between gases and liquids decreases until it is almost the same.
When work­ing with high-pres­sure sys­tems, it is advis­able to wear hear­ing pro­tec­tion, as sud­den changes in pres­sure, for example when a rup­ture disc safety device is triggered, can cause sud­den noise and oth­er­wise dam­age your hear­ing. Work­ing behind a pro­tect­ive wall is gen­er­ally recom­men­ded, as a pres­sure wave can also lead to injur­ies if a com­pon­ent fails.

1.5 Life­time
Machine com­pon­ents can fail after some time due to unfore­seen chem­ic­al and mech­an­ic­al influ­ences. On the oth­er hand, exper­i­ence has shown that employ­ees become less care­free over time with acci­dent-free oper­a­tion.
High-pres­sure com­pon­ents are often designed in such a way that they do not have an infin­ite ser­vice life!
The res­ist­ance to load changes, and thus the ser­vice life of many com­pon­ents, espe­cially when they are under high pres­sure, is lim­ited. In addi­tion, it is very dif­fi­cult to cal­cu­late and is often mis­judged.
An error in the selec­tion of the mater­i­al, in the mater­i­al, in the con­struc­tion or in the pro­duc­tion can also have effects that allow a com­pon­ent to bear its load only for a lim­ited peri­od of time.
A short pres­sure test or an approv­al by an expert is no guar­an­tee that a pres­sure-bear­ing com­pon­ent will have a per­man­ent ser­vice life.
You should there­fore always work with your print­ing sys­tem in such a way that a fail­ure of a com­pon­ent can­not injure any­one!
If it is unavoid­able to work dir­ectly on pres­sur­ized parts, always wear pro­tect­ive goggles, a hard hat, safety shoes and pro­tect­ive cloth­ing. Wear ear­muffs if you expect loud noises.
Any­one who works unpro­tec­ted on pres­sur­ized sys­tems is not act­ing cour­ageously, but irresponsibly!

2 Pro­tocol

If you oper­ate com­pon­ents that are sub­ject to accept­ance in accord­ance with the Pres­sure Equip­ment Dir­ect­ive, the AD 2000 Dir­ect­ive stip­u­lates that a record must be kept. The AD 2000 set of rules dom­in­ates in Ger­many, but is increas­ingly being replaced by DIN EN 13445.

2.1 Pro­tocol con­tent
Work on a high-pres­sure sys­tem should gen­er­ally be recor­ded.
Nor­mal occur­rences such as pres­sure and tem­per­at­ure loads, their peri­ods of time, job descrip­tions, exten­sions, repairs and irreg­u­lar­it­ies should be recor­ded in the log.
One per­son should nev­er work alone with a high-pres­sure sys­tem. The people who work with the high-pres­sure sys­tem must be recor­ded in the pro­tocol. If sys­tems have to work unsu­per­vised, it must be recor­ded in the log who is respons­ible for the run­ning sys­tem, where the respons­ible per­son can be found, and how the sys­tem is to be handled in the event of a fault.

3 Con­di­tions

3.1 Gen­er­al
In order to pre­vent pre­ma­ture fatigue and inat­tent­ive­ness of the staff, the work­place must cor­res­pond to a nor­mal work­place in terms of light­ing, tem­per­at­ure con­trol, vent­il­a­tion and noise pol­lu­tion.
In gen­er­al, the install­a­tion site should be well vent­il­ated, espe­cially when work­ing with flam­mable or tox­ic sub­stances. A suit­able sys­tem for the safe remov­al of any sub­stances that may escape through safety devices must be guar­an­teed.
The work­place must at least be equipped with a fire extin­guish­er, first aid kit and a tele­phone.
Suit­able tools must be avail­able for ser­vice or repair work.

3.2 Gas sys­tems
When work­ing with gas sys­tems, depend­ing on the size of the pres­sur­ized volume, it may be neces­sary to provide a blow-out wall, auto­mat­ic­ally open­ing flaps or sim­il­ar relief options.
When work­ing with flam­mable gases, a suit­able, reg­u­la­tion-com­pli­ant exhaust sys­tem must be provided. When work­ing with liquids whose tem­per­at­ure is high­er than the self-igni­tion tem­per­at­ure of the liquid, the appar­at­us must be placed in a con­tain­er filled with nitrogen.

3.3 Pro­tect­ive walls
Although it is pos­sible to cal­cu­late the required strength of pro­tect­ive walls, this is unlikely to make much sense in prac­tice; it should be determ­ined by exper­i­enced spe­cial­ists.
The walls should be mul­tilayered. For lar­ger sys­tems, a com­bin­a­tion of a 10mm polycar­bon­ate sheet, a 2mm sheet steel and a sharp-edged wood lay­er adap­ted to the applic­a­tion has proven to be very effect­ive. A 2mm sheet steel should be attached to the out­side.
The pro­tect­ive walls must be well secured so that people are not endangered by fall­ing over after an impact.
A simple con­crete wall is not well suited to lar­ger sys­tems. Although the impact­ing body does not pen­et­rate the wall, as we have already exper­i­enced, a part on the back can loosen and fly on.

3.4 Burst pro­tec­tion con­tain­er
Burst pro­tec­tion con­tain­ers are often safer and cheap­er than pro­tect­ive walls.

3.5 walls and ceil­ings
Nev­er rely on the pro­tect­ive effect of the adjoin­ing walls and ceil­ings, it is usu­ally less than is gen­er­ally assumed.

3.6 Win­dows
If you place your sys­tem in front of a glass win­dow, make sure you are aware of the con­sequences of any broken glass.
The view of a high pres­sure sys­tem enables:
Polycar­bon­ate offers lim­ited pro­tec­tion that is mostly over­rated. Single-walled polycar­bon­ate, e.g. 10mm thick, does not offer any pro­tec­tion worth men­tion­ing. Two-lay­er polycar­bon­ate offers bet­ter pro­tec­tion up to approx. 3 kbar. Stable frames are very import­ant.
We car­ried out sev­er­al shot attempts with polycar­bon­ate win­dows. The res­ults were sober­ing. Let us advise you per­son­ally.
“Plexiglas” should not be used under any cir­cum­stances. “Armored glass” offers the best pro­tec­tion for high-pres­sure sys­tems (see also
TV cam­er­as are also a
n altern­at­ive on occasion.

3.7 Con­trol ele­ments
Of course, all con­trols must be out­side of the print area.

3.8 Iden­ti­fic­a­tion
The emer­gency reg­u­la­tions and meas­ures for switch­ing off the sys­tem in an emer­gency are clearly vis­ible out­side the danger area.
A high-pres­sure room must be marked accord­ingly from the outside.

4 Com­pon­ents

4.1 Mater­i­al
When select­ing the com­pon­ents, par­tic­u­lar atten­tion should be paid to the choice of mater­i­als. Each mater­i­al has dif­fer­ent phys­ic­al and chem­ic­al prop­er­ties. The user should also ask him­self which by-products may arise in a reac­tion, under which bound­ary con­di­tions (tem­per­at­ure, pres­sure, cata­lysts) and how this can be pre­ven­ted. Nev­er­the­less, the mater­i­al must be suit­able to safely guide these fluids.

4.2 Gas bottles
Spe­cial atten­tion should be paid to stand­ard gas cyl­in­ders, as they often store a very high energy poten­tial.
Gas cyl­in­ders are not always in good con­di­tion and the pre­scribed test inter­vals are cur­rently far too long.
The gas cyl­in­ders must not be set up in such a way that they can be dam­aged if a high-pres­sure com­pon­ent fails.
It is best to store gas cyl­in­ders out­doors, pro­tec­ted from the sun, locked and closed. See TRB 610.
It is not per­mit­ted to fill gas cyl­in­ders your­self. Ser­i­ous acci­dents are not infre­quently the res­ult of violations.

4.3 Pres­sure gauges
With pulsat­ing pres­sures, pres­sure gauges may only be used up to 2/3 of their dis­play range. They should have an intern­al pro­tect­ive wall (spe­cial secur­ity / sol­id front). Only safety glass may be used as a front pane. A liquid filling is usu­ally recom­men­ded. At pres­sures above 1000 bar, pres­sure gauges with a high pres­sure con­nec­tion should be used.
Pres­sure trans­ducers usu­ally have a high­er load capa­city than pres­sure gauges. A safe con­struc­tion should be ensured with regard to a fail­ure of the mem­brane or the pres­sure pipe.
Manu­al valves are a very crit­ic­al com­pon­ent, as the oper­at­or comes into dir­ect con­tact with them.
The con­struc­tion of many hand valves is unsafe. The gland nut can tear off or unscrew. Many lock­ing plates, which are sup­posed to pre­vent the stuff­ing box nut from being unscrewed, are insuf­fi­cient and only inad­equately serve this pur­pose. Valves with an addi­tion­al pro­tect­ive cap or a yoke over the stuff­ing box nut are bet­ter.
Pneu­mat­ic­ally, elec­tric­ally or hydraul­ic­ally oper­ated valves are safer than manu­al valves, as they do not have to be in the vicin­ity of the oper­at­or. In addi­tion, they are often also cheap­er, since less pip­ing work has to be car­ried out and they often also have a longer ser­vice life.

4.4 High pres­sure con­nec­tions
High pres­sure con­nec­tions must have at least one relief hole.
In the event of a leak, the pres­sure loads the entire area of the thread of the pres­sure screw. In the case of a 10,000 bar M16x1.5 screw con­nec­tion, the res­ult is 100 times the load ((16𝑚𝑚) 2 (1.6𝑚𝑚) 2 = 100). Without a relief hole, the pres­sure screw would tear off and turn into a pro­jectile.
The area of the relief bores should have at least 1/4 of the area of the nom­in­al width, but at least a dia­met­er of 2.5mm.
Example: Nom­in­al size 8mm, two relief holes Dia­met­er of the relief hole: √ (8𝑚𝑚) 24/2 = 2.8 mm.
The cor­rect nom­in­al dia­met­er of the relief bore can eas­ily be cal­cu­lated using the nozzle for­mula, tak­ing into account the max­im­um dis­charge volume.

4.5 High pres­sure pipes
High pres­sure pipes should be designed in accord­ance with DIN EN 13445.
If they trans­port tox­ic, flam­mable or caustic flu­ids, or if a cer­tain pres­sure liter product is exceeded, they are sub­ject to accept­ance (see Pres­sure Equip­ment Dir­ect­ive).
Pipes should be fastened at inter­vals of 500 to 1000 mm. Oth­er­wise, if the pipe ends fail, it could cause ser­i­ous injury.
The bend­ing radi­us must not be less than five times the pipe dia­met­er. Cold-hardened pipes, which is cur­rently most stain­less high-pres­sure pipes, must not be hot-bent, wel­ded or soldered, or heated to over 750 ° C, oth­er­wise they will lose their work-hardening.

4.6 High pres­sure hoses
Work­ing with high-pres­sure hoses that are oper­ated at pres­sures of up to 4000 bar is very dan­ger­ous without addi­tion­al pro­tec­tion. Par­tic­u­larly when oper­at­ing hydro­form­ing sys­tems, high-pres­sure hoses are occa­sion­ally used in an irre­spons­ible man­ner.
With regard to the accept­ance reg­u­la­tions, hoses are to be treated like pipes.
Addi­tion­al pro­tect­ive devices, such as pro­tect­ive hoses, can be sup­plied for high-pres­sure hoses. Dif­fer­ent types of pro­tect­ive hoses are avail­able: a clear PVC pro­tect­ive hose, which is primar­ily used as abra­sion pro­tec­tion, and a burst pro­tec­tion hose, which is much more stable. Fire­proof pro­tect­ive hoses can be used for high­er tem­per­at­ures. A simple, flex­ible one or two-lay­er hydraul­ic hose can be used as a burst pro­tec­tion hose. The pro­tect­ive hose ends can be made open or closed. When the ends are closed, there is the pos­sib­il­ity of a con­trolled dis­charge of the flu­id.
The hoses must be provided with a tear-off pro­tec­tion. This pre­vents the con­nec­tion or hose from fly­ing away if the crimp­ing fails.
Instead of hoses, spir­al-shaped pipes, the lin­ear feed-throughs developed by us or pipes with rotary feed-throughs can often be used. These have a sig­ni­fic­antly high­er level of safety, longer ser­vice life and lar­ger nom­in­al sizes.

4.7 Over­pres­sure safety devices
4.7.1 Burst disc safety devices
The cross-sec­tion of burst disc safety devices is spe­cified in AD 2000 reg­u­la­tions and the neces­sary rup­ture pres­sure of the burst discs must be at least 30% above the oper­at­ing pres­sure.
The entire sys­tem must be designed for at least the burst­ing pres­sure of the burst discs or the open­ing pres­sure of an over­pres­sure or safety valve.
A suit­able dis­charge of the escap­ing flu­id must be avail­able.
Burst discs are sub­ject to fatigue with a high­er degree of util­iz­a­tion and pulsa­tions. In such cases, pre­ma­ture burst­ing is to be expec­ted.
Burst discs should primar­ily be used in sys­tems in which a sud­den increase in pres­sure is to be expec­ted or which are dif­fi­cult to seal. Oth­er­wise, pres­sure relief valves are more recommended.

4.7.2 Pres­sure relief valves
Pres­sure relief valves, also known as pres­sure relief valves, which have been approved through a type test or indi­vidu­al accept­ance by an expert, are called safety valves.
Pres­sure ves­sels or sys­tems that are sub­ject to accept­ance must have a safety valve or an approved rup­ture disc safety device. There must be no shut-off facil­ity between the pres­sure ves­sel and the safety device.
The open­ing pres­sure of the pres­sure relief valve may not exceed the oper­at­ing pres­sure by more than 10%.

4.8 Pres­sure ves­sels
Pres­sure ves­sels with an oper­at­ing pres­sure of over 0.5 bar are sub­ject to accept­ance by the man­u­fac­turer or an expert in accord­ance with the Pres­sure Equip­ment Dir­ect­ive. The cor­res­pond­ing set of rules is too extens­ive for its con­tent to be repro­duced in a few para­graphs, but can be looked up on the web­site linked above in the text.
A test book must be avail­able for every pres­sure ves­sel that is sub­ject to accept­ance.
In this book, in the cer­ti­fic­ate for the pre­lim­in­ary test and in the accept­ance test cer­ti­fic­ate, the per­mit­ted load changes, per­mit­ted oper­at­ing pres­sure, per­mit­ted oper­at­ing tem­per­at­ure and per­mit­ted flu­id, as well as inter­vals for the repeat test and the oth­er approv­al cri­ter­ia are recor­ded.
Extern­ally heated pres­sure ves­sels that are heated under pres­sure are sub­ject to spe­cial reg­u­la­tions. Auto­claves are usu­ally designed to be heated first, then pres­sur­ized. In the oppos­ite case, a neg­at­ive state of ten­sion arises, i.e. the warm out­er wall expands more than the cold inner wall. This can cause the con­tain­er to fail.
In many cases, intern­al heat­ers are cheap­er and react much faster. We sup­ply intern­al heat­ers up to 10,000 bar pres­sure.
Par­tic­u­lar care should be taken when open­ing pres­sure ves­sels that con­tain heated liquids, espe­cially water. If the water is just below boil­ing point, pulling out the cap often cre­ates a vacu­um that can lead to a steam explo­sion. Ser­i­ous scalds can result.

4.9 Machine com­pon­ents
Machine parts that have pres­sure-bear­ing com­pon­ents, e.g. B. Pumps and com­pressors, do not fall under the pres­sure equip­ment dir­ect­ive, but must be designed with a spe­cial safety.
This par­tic­u­lar secur­ity con­sists in the fact that a safety factor of 3 instead of 1.5 should be used when the yield point is used. Since this is impossible with most high-pres­sure devices, these are, in the opin­ion of many experts, but not all, to be removed as an altern­at­ive to pres­sure ves­sels.
There are spe­cial accept­ance reg­u­la­tions for pres­sure intensifiers.

4.10 Pres­sures
4.10.1 Stat­ic pres­sures
Com­pon­ents that are stat­ic­ally loaded and below the endur­ance lim­it the­or­et­ic­ally have an infin­itely long ser­vice life if they are prop­erly constructed.

4.10.2 Dynam­ic pres­sures
An abso­lutely reli­able math­em­at­ic­al design over the ser­vice life of machine com­pon­ents under high pres­sure and strong load changes is not pos­sible. The dynam­ic pres­sures recom­men­ded by us are empir­ic­al val­ues with a medi­um load.

5 Pres­sure systems

Pres­sure sys­tems may only be oper­ated if they com­ply with the applic­able CE reg­u­la­tions.
This includes, among oth­er things, that all applic­able reg­u­la­tions are observed and that they have been pro­duced by com­pet­ent spe­cial­ist per­son­nel.
A prop­er oper­at­ing manu­al must be available.

5.1 Dan­ger­ous high pres­sure sys­tems
Spe­cial reg­u­la­tions apply to sys­tems that con­tain tox­ic, flam­mable or caustic flu­ids and to a large num­ber of spe­cial sys­tems (see DIN EN 13445).

5.1.1 Oxy­gen
Oxy­gen sys­tems under high pres­sure are dan­ger­ous and are sub­ject to spe­cial reg­u­la­tions (see “Hand­ling oxy­gen”, leaf­let M034, trade asso­ci­ation for the chem­ic­al industry and UVV oxy­gen).
Oxy­gen sys­tems must not be lub­ric­ated with nor­mal oils or greases. There is a risk of explo­sion!
Oxy­gen must not be used in place of com­pressed air. Cloth­ing soiled with oil or grease must not be worn when work­ing with oxy­gen. Oxy­gen must not be blown into cloth­ing! Avoid touch­ing parts that come into con­tact with oxy­gen with greasy fin­gers. Oxy­gen may only be used in com­pon­ents that are inten­ded for oper­a­tion with oxy­gen.
Oxy­gen sys­tems may only be cleaned with suit­able solvents.
Leak tests may only be car­ried out by experts who have exper­i­ence with leak tests and in deal­ing with oxy­gen.
Only plastics that have been tested and found to be suit­able may be used. Pres­sure ves­sels that are sub­ject to accept­ance must be approved for oxy­gen. You have to be abso­lutely clean. There must be no chips or burrs in the sys­tem. Edges should be roun­ded.
Only pres­sure gauges (mano­met­ers) with the label “Oxy­gen! Keep oil and grease free ”should be used.

5.1.2 Hydro­gen
Hydro­gen is highly flam­mable and dif­fi­cult to seal due to its low vis­cos­ity. In many steels, con­tact with hydro­gen leads to imme­di­ate embrit­tle­ment and crack­ing. This usu­ally res­ults in burst­ing with accom­pa­ny­ing igni­tion of the gas.
Only use mater­i­als suit­able for hydro­gen for oper­a­tion with hydrogen!

5.1.3 Acet­ylene
Acet­ylene or ethyl­ene sys­tems must be free of cop­per and sil­ver. This also applies to all indi­vidu­al parts, such as seals or valve glands.
There are pre­cise reg­u­la­tions with regard to install­a­tion and oper­a­tion.
There is TRAC 203 for oper­at­ing reg­u­la­tions for acet­ylene com­pressors, and TRAC 204 for pipes car­ry­ing acetylene.

5.1.4 Nitro­gen
Breath­ing in nitro­gen without oxy­gen can lead to sud­den death. Nitro­gen can embrittle steels at high­er tem­per­at­ures. Argon should prefer­ably be used at high­er temperatures.

5.1.5 Liquids
In the case of liquids, their solid­i­fic­a­tion point must be observed.
It is not uncom­mon for incid­ents to occur because the liquid has solid­i­fied, the pres­sure gauge shows no increase in pres­sure and the load on the sys­tem has increased fur­ther until it bursts.
Hydraul­ic oils solid­i­fy at 20 ° C at approx. 3000 bar, water at 20 ° C at approx. 7500 bar. In the case of nar­row cross-sec­tions, solid­i­fic­a­tion begins con­sid­er­ably earli­er than in the case of lar­ger cross-sec­tions.
You can obtain flu­ids suit­able for high pres­sures from us.

5.2 Con­stel­la­tion test
If you have received com­pon­ents that are sub­ject to accept­ance and have been approved by an expert and these have been set up, an expert must carry out the install­a­tion test in accord­ance with DIN EN 13445. Only then may your sys­tem be oper­ated for the per­mit­ted period.

5.3 Tem­per­at­ure mon­it­or­ing
In the case of heat­able sys­tems, any sub­sequent pres­sure increase due to the great­er expan­sion of the tem­per­at­ure-con­trolled flu­id must be taken into account. A removed tem­per­at­ure lim­it­ing device must ensure that the inten­ded oper­at­ing tem­per­at­ure is maintained.

6 Ser­vice work

6.1 Pro­ced­ure
As soon as ser­vice work is car­ried out on a sys­tem or device, the sys­tem must be switched off and the pres­sure released.
Check that all pres­sure gauges are not show­ing any pres­sure.
The drain valve must be open.
If the sys­tem is oper­at­ing at an elev­ated tem­per­at­ure, wait until a nor­mal tem­per­at­ure is reached.
Depend­ing on the type of activ­ity, the com­pressed air, the elec­tric­al voltage or the high-pres­sure con­nec­tion should be disconnected.

6.2 High pres­sure screw con­nec­tions
Do not loosen any high pres­sure screw con­nec­tion that is under pres­sure.
Do not attempt to tight­en a leak­ing high pres­sure fit­ting that is under pres­sure!
You can des­troy the com­pon­ent in this case, as the mech­an­ic­al load of your tight­en­ing torque is added to the pres­sure load.
Only use com­pon­ents that are designed for the oper­at­ing pres­sure.
Use a suit­able lub­ric­ant when assem­bling all high pres­sure fittings. 

6.3 Leaks
All leaks must be repaired imme­di­ately. A per­man­ent leak can be very dan­ger­ous. It is there­fore for­bid­den for our per­son­nel to pres­sur­ize a sys­tem if there is a leak.
Turn off the sys­tem, depres­sur­ise and repair the leak.

6.4 Gen­er­al safety inform­a­tion
Only repair com­pon­ents for which you have a usable and prop­er oper­at­ing manu­al.
Do not try to make spare parts your­self.
Check wheth­er your sys­tem still com­plies with the applic­able safety reg­u­la­tions.
The recur­ring tests in accord­ance with the manufacturer’s inform­a­tion and the pres­sure equip­ment dir­ect­ive must be observed.
Call us in case of doubt!