8/10/2019 20_Liebsch - EN14175-7

1/28

The new European Standard EN 14175-7

Fume Cupboards for high heat and acidic load

Put into practice

8/10/2019 20_Liebsch - EN14175-7

2/28

Introduction

Requirements of the European Standard EN 14175-7

High heat load - influence to the fluid mechanics

Put into practice

Summary

Content

8/10/2019 20_Liebsch - EN14175-7

3/28

EN 14175-7

Fume cupboards for high heat and acidic load

This European Standard was approved by CEN on 27 April 2012.

EN 14175-7 shall be given the status of a national standard at the latest

by November 2012.

Conflicting national standards shall be withdrawn by November 2012 at

the latest.

Introduction

8/10/2019 20_Liebsch - EN14175-7

4/28

EN 14175-7

Fume cupboards for high heat and acidic load

This European Standard exists in three official versions

(English, French, German).

CEN members are the national standards bodies of Austria, Belgium,

Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Germany, Estonia,

Finland, France, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey, and the United Kingdom.

Introduction

8/10/2019 20_Liebsch - EN14175-7

5/28

EN 14175 consists of the following parts,

under the general title Fume cupboards:

Part 1 - 2003: Vocabulary

Part 2 - 2003: Safety and performance requirementsPart 3 - 2004: Type test methods

Part 4 - 2004: On-site test methods

Part 6 - 2006: Variable air volume fume cupboards

Part 7 - 2012: Fume cupboards for high heat and acidic load

Part 5 2006 (Recommendations for installation and maintenance) has

been published as Technical Specification CEN/TS 14175-5.

Introduction

8/10/2019 20_Liebsch - EN14175-7

6/28

EN 14175-7 applies for

fume cupboards for high heat load

fume cupboards for high heat load

in combination with acidic digestions

fume cupboards for handling of perchloric acid

fume cupboards for handling of hydrof luoric acid

This European Standard applies in conjunction with EN 14175-1 to EN

14175-4 and, where appropriate, to EN 14175-6 and specifies

supplementary information relevant to vocabulary, safety and

performance requirements, type test methods, on-site test methods and

marking of the listed special purpose fume cupboards.

Introduction

8/10/2019 20_Liebsch - EN14175-7

7/28

Requirements of EN 14175-7

Basic safety and performance objectives

Materials

Safety requirements

Testing

Services

Product manual

Marking and labelling

Declaration of conformity

EN 14175-7

8/10/2019 20_Liebsch - EN14175-7

8/28

Fume cupboards for high heat load

Basic safety and performance objectives

In accordance with EN 14175-2 with the following supplement:

The design and construction of the fume cupboard shall ensure the

safety and performance objectives when high heat loads are present in

the workspace.

Materials

In accordance with EN 14175-2 with the following supplements:

The selection of materials, whether they are glass, plastics or from

other kind, shall ensure suitability against chemical erosion and thermaldeformation at the temperature of use.

NOTE: If glass is used for the front sash, authorities or purchasers in

some European countries require laminated safety glass in

accordance with the definition given in EN ISO 12543-1:2011, 3.2.

Requirements

8/10/2019 20_Liebsch - EN14175-7

9/28

Fume cupboards for high heat load

Airflow

In accordance with EN 14175-2 with the following supplement:

Effects on airflow caused by thermal loads and location of heating

appliances within the workspace shall be considered and limited.

Maximum temperature alarm

Fume cupboards for high thermal load shall be equipped with a

temperature sensor in the top of the fume cupboard with an alarm

showing when the maximum exhaust air temperature as specified in the

product manual is exceeded. It should be possible to relay the alarm.

Requirements

8/10/2019 20_Liebsch - EN14175-7

10/28

Fume cupboards for high heat load

Requirements

Testing

Type testing shall be performed

according to EN 14175-3 and on-site

testing according to EN 14175-4 withthe following supplement:

During the tests two heating plates

shall be in the fume cupboard's

workspace. Containment and

robustness shall each be tested

without thermal load (heating plates

switched-off) and with a thermal load

of 4 kW per meter internal clear

width.

8/10/2019 20_Liebsch - EN14175-7

11/28

Fume cupboards for high heat load

Declaration of conformity

A declaration of conformity shall clearly state the temperature range

at which the fume cupboard for high heat load may be used and that

the materials and construction of the fume cupboard are suitable for this

temperature range.

Requirements

8/10/2019 20_Liebsch - EN14175-7

12/28

Fume cupboards for high heat load and acidicdigestions

Basic safety and performance objectives

The design and construction of the fume cupboard

shall ensure the safety and performance objectives when high heat

loads are present in the workspace

shall avoid dangerous concentrations and deposits by acids or

hydroxides emitted in the workspace and shall withstand the increased

requirements during the intended time of use.

Requirements

8/10/2019 20_Liebsch - EN14175-7

13/28

Fume cupboards for high heat load and acidicdigestions

Materials

In accordance with EN 14175-2 with the following supplements:

The selection of materials shall ensure suitability against chemical

erosion by acids and acidic fumes and thermal deformation at the

temperature of use.

Acid vapour developed during acidic digestions is extremely viscous

and will adhere to surfaces with which it is in contact. Materials should

have smooth surfaces which can be easily cleaned.

Requirements

8/10/2019 20_Liebsch - EN14175-7

14/28

Fume cupboards for perchloric acid

Basic safety and performance objectives

In accordance with EN 14175-2 with the following supplement:

the design and construction of the fume cupboard shall ensure

avoidance of dangerous deposits and of dangerous reactions with

materials used in the construction of the fume cupboard when handling

perchloric acid in the workspace.

NOTE 1: Typical temperatures in the workspace during perchloricprocess work can be in the region of 120 C to 160 C.

NOTE 2: Choice of materials and construction of the exhaust ductwork

for perchloric acid fume cupboards needs special attention when

designing the laboratory.

Requirements

8/10/2019 20_Liebsch - EN14175-7

15/28

Fume cupboards for hydrofluoric acid

Materials

In accordance with EN 14175-2 with the following supplements:

All parts of the fume cupboard and of the extract air ducts that will be in

touch with hydrofluoric acid or hydrofluoric acid vapour shall be made of

materials that are resistant against hydrofluoric acid.

NOTE: Safety data sheets for hydrofluoric acid can give guidance

regarding substances reacting with fluorides.The material for the sash between the operator and the workspace

shall be suitable plastics material that meets the performance

objectives.

Requirements

8/10/2019 20_Liebsch - EN14175-7

16/28

High heat load - influence to the fluid mechanics

To implement the requirements of the DIN EN 14175-7 standard into

practical work, particularly with regard to the effects of the high heat

load, theoretical preliminary considerations and experimental

examinations are useful.

Fluid mechanics

8/10/2019 20_Liebsch - EN14175-7

17/28

Temperature rise

Fluid mechanics

8/10/2019 20_Liebsch - EN14175-7

18/28

Temperature rise

Fluid mechanics

On the assumption of an exhaust airf low of 600 m/h and a heat

capacity of 6 kWfor a fume cupboard with a width of 1500 mm the

following result is obtained:

8/10/2019 20_Liebsch - EN14175-7

19/28

Temperature rise

According to the theoretical calculation the temperature of the air intake

in the fume hood would increase for almost 30 C.

Measurements during the experiment show that the heating of the air

that is flowing through the fume hood is slightly lower in reality, because

part of the heat energy is absorbed by the fume hood casings material

and released to the outside through its surface.

Fluid mechanics

8/10/2019 20_Liebsch - EN14175-7

20/28

Temperature rise

Temperature measurement at different locations in the fume cupboard

show that due to the heat radiation of the heating plates the surfacesof

the fume cupboard interior in the radiation area, e.g. on the fume

cupboard rear wall, will be heated up to a temperature of 95 C, or on

the inside of the sash up to a temperature of 65 C.

Therefore the manufacturers of fume cupboards for high heat load

shall take care of a sufficient temperature resistance when selecting the

materials to be used. Furthermore they also have to take into account

more extensive effects such as e.g. a strong heating of operationdevices.

Fluid mechanics

8/10/2019 20_Liebsch - EN14175-7

21/28

Computational fluid dynamics - CFD

The influences of high heat load to the flow mechanics of the fume

cupboard can be illustrated by means of e.g. a numerical flow

simulation.

Fluid mechanics

8/10/2019 20_Liebsch - EN14175-7

22/28

Put into practice

Airflow in consideration of high

heat load

Put into practice

http://en7_smoke_hot-cold.wmv/

8/10/2019 20_Liebsch - EN14175-7

23/28

Temperature Alarm

Put into practice

BMS

sensor

alarm

8/10/2019 20_Liebsch - EN14175-7

24/28

Temperature Controlvariable flow rate

Put into practice

BMS

sensor

sash

alarm

damper

VAV

controller

8/10/2019 20_Liebsch - EN14175-7

25/28

TestingRobustness of containment

according to EN 14175-7

Put into practice

8/10/2019 20_Liebsch - EN14175-7

26/28

TestingRobustness of containment

according to EN 14175-7

Put into practice

8/10/2019 20_Liebsch - EN14175-7

27/28

SummaryWhile the previous series of EN 14175 standards exclusively described

isothermal conditions in the fume cupboard, the newly issued part 7

offers the option to assess the safety of fume cupboards at high heat

load. This closes an essential gap, as works with sources of heat in a

fume cupboards are part of the daily routine in many laboratories.

Now it is not least up to the manufacturers to translate the non-trivial

requirements of the standard into innovative solutions and to also

contribute to the safety and power efficiency for the operation of

special application fume cupboards in laboratories.

EN 14175-7

8/10/2019 20_Liebsch - EN14175-7

28/28

Juergen Liebsch