G/TBT/N/THA/3 22 
Explanatory Memorandum  
Of the draft ministerial regulation  on high efficien cy double -capped fluorescent lamps   
B.E. …  
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Principle  
Definitions  of high e fficien cy double -capped fluorescent l amps  
Rationale  
It is hereby deemed  appropriate and necessary  to define  a double -capped fluorescent 
lamp  that has an energy consumption value not lower  than is specified in this ministerial 
regulation as a high efficien cy double -capped fluorescent lamp . The objective s of this 
regulation  are to conserve  energy , to provide manufacturers and sellers  of such product s with 
the right to support and assistance from the Ener gy Conservation Promotion Fund, and to 
allow consumers  to have the option to use high efficien cy double -capped fluorescent lamp s. 
This will promote the country’s energy consumption efficiency  and reduce pollution.   
DRAFT  
Ministerial Regulation  
Definitions of high efficien cy double -capped fluorescent lamps  
B.E. … 
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In accordance with S ection 6, Clause 2 and Section 23, Clause  1(2) and Clause 3 of 
the Energy Conservation  Promotion Act, B.E. 2535, with amendments made to the Energy 
Conservation  Promotion Act  (Issue 2), B.E. 2550   contain ing a number of  provisions related to 
the limitation of private rights and liberties as permitted  in Section 29, together  with Section 
33, Section 41 and Section 43 of the Constitution  of the Kingdom of Thailand  – with  the 
guidance of the National Energy Policy Committee  – the Minister of Energy  issues a  
ministerial re gulation as follows:  
1. In t his ministerial regulation:  
“Double -capped fluorescent lamp” mean s a hollow tube  fluorescent lamp  in a linear 
shape  for general lighting that is  used with separate receptacles , single phase alternating 
current at the maximum of  250 volts, and a frequency of 50 Hertz . Excluding : colour double -
capped fluorescent lamps , or those  generat ing invisible off-spectrum light ; double -capped 
fluorescent lamps for colo ur matching wh ere colo ur appears  at one point of a black  body 
locus ; double -capped fluorescent lamps for use in industrial and agricultural processes ; 
double -capped fluorescent lamps for medical purposes ; and double -capped fluorescent lamps 
restricted by law to be used only in specific condition s other  than  general lighting  and c an be 
distinguished from those for general lighting , with sizes  specified in this ministerial regulation.  
"Energy consumption efficiency value” means the initial efficacy value, maintained  
efficacy value and general colour render ing index.  
“Efficacy value” means the ratio of luminous  flux over input power of a double -capped 
fluorescent lamp under a specified measurement state . 
“Initial efficacy value” means the measured efficacy value of a new double -capped 
fluorescent lamp that has been in use for 100 hour s. 
“Maintained  efficacy value” means the measured efficacy value of a double -capped 
fluorescent lamp that has  been in use  for 5  000 hours.  
“General colour render ing index” means  a relative value of object  colour shift when 
illuminated  from a specified ligh t source  to match  an object’s colo ur that appear s under a 
reference light source .  2. A high efficien cy double -capped fluorescent lamp must have an energy 
consumption efficiency value no t lower  than that specified and announced by the Minister , 
considerin g the economic situation, the  government’s energy polic y, the readiness of double -
capped fluorescent lamp  manufactur e and sales, and support , as well as  support and 
assistance provided to the manufacturers and sellers of double -capped fluorescent lamps . 
The energy  consumption efficiency  value must be defined in respect to the length and 
wattage power specified by the manufacturers as follows:  
(1) The initial efficacy  value 
Specified lamp length (mandatory)  
(millimetres ) Less than 
550 From 550  
to less than 
700 From 700  
to less than 
1 150 From 1  150 
to less than 
1 350 
Power wattage specified by 
manufacturers ( recommended)  
(watts) Less than 16  16 to 24  17 to 40  28 to 50  
Initial efficacy value 
(lumen s per watt)  87.0-94.0 68.0-75.0 94.0-100.0  88.0-96.0 
 
(2) Th e main tained efficacy  value of a double -capped fluorescent lamp with length 
and pow er as specified in (1) must not be less than 90% of the initial efficacy  value of a lamp 
with the same length and power.  
(3) The general  colour render ing index of a double -capped fluorescent lamp  for all 
length s as specified in (1) must not be less than 80% .  
3. The formula  for calculating  the energy efficiency value of a double -capped 
fluorescent lamp  is as follows:  
 
(1) The initial efficacy  value 
F100 = L test.ref/Ptest 
 
F100 means  initial efficacy  value . The unit is lumen s per watt.  
Ltest.ref means  luminous  flux of a double -capped fluorescent 
lamp being tested with a reference ballast. The 
unit is the lumen.  where 
Ptest means  wattage  of a double -capped fluorescent lamp  
being tested . The unit is the watt.  
(2) The main tained efficacy  value is calculated by estimating the luminous  flux 
value outside the linear range from the initial e fficacy  value  past the luminous  flux data point 
from more than 2  000 hours to 5  000 hours.   
 4. The test  for determining  the energy consumption efficiency value of a double -
capped fluorescent lamp  must be carried out by the organi sations specified and announced 
by the minister.  
5. The standard  and methodology of the test for determining  the energy consumption 
efficiency value of a double -capped fluorescent lamp  must comply with the specifications as 
published  by the minister .  
 
Given on:  B.E. 
 
Minister of Energy