The training area is still quite an interesting explore. There's several ways in if you look for a bit.
There's some good aerial photos here:
English – Coflein
There's an interesting description of the process:
A history of the Royal Navy Propellant Factory, Caerwent
by Medwyn Parry
©1997, Medwyn Parry
The Royal Naval Propellant Factory always remained something of a mystery.
The man in the street could understand the meaning of shells, bombs,
explosives etc., but the word "propellant" was confusing. It is not
surprising that occasionally the establishment was referred to as the Royal
Navy Repellent Factory or even the Royal Navy Propeller Factory. The extreme
misrepresentation came when a letter was sent to a former female employee,
addressed RNPF Convent, and began "Dear Mother Superior".
In the first months of the First World War the First Lord of the Admiralty,
Winston Churchill, insisted on the necessity of the Royal Navy having its
own independent supply of propellant. Conflicts at sea required greater
accuracy and uniformity of ballistics than on land. This could best be
achieved by a specialist factory devoted to manufacturing a higher grade
propellant solely for the Navy.
Production of solvent based propellants began for the Royal Naval Cordite
Factory at Holton Heath, Dorset in 1915. Considerable advances were made at
the establishment in the development and production of various types of
explosives. After 1918 many ordnance factories were closed, but the
Admiralty established the Naval Ordnance Inspection Laboratory at Holton
Heath in 1919, to develop new products and perfect the manufacturing
techniques. This work led to new types of Solventless Cordite ("SC") and its
variants which had certain advantages over the older products. They were
easier to manufacture, did not use acetone, had better uniform ballistic
characteristics, and contained Centralite (or Carbamite) as a stabiliser -
giving the propellant a far longer service life.
In 1920 Britain's annual defence budget was Ł292,000,000, and by 1932 had
been reduced to an inter-war low of Ł103,000,000.
The 1930s had begun with great political optimism, however within a few
short years the situation would change dramatically. The decay in
international diplomatic relations, culminating in an act of aggression by
Japan in occupying Manchuria and withdrawing from the League of Nations.
Then Germany, following its lack of success in obtaining any agreement at
the World Disarmament Conference in 1933, also withdrew from the League. In
open defiance of the Versailles Treaty, Hitler started a programme of
rearmament of Germany. Within three years it had militarised the Rheinland,
then in 1938 forced the Anchluss Union with Austria.
In 1935 Italy invaded Abyssinia, to try and establish a North African
empire. Britain and France both had neighbouring territories and were
greatly worried by Italian aggression. Their main supply lines passed
through the British controlled Suez Canal.
It was with this background of international tension that Britain began to
reassess its munitions requirements as the possibility of a global conflict
once again seemed an inevitable outcome. The cordite factory at Holton Heath
could produce a maximum of 156 tons of cordite per week. The Chief
Superintendent of Supply, H.J. Burnett-Hall needed a second factory, capable
of producing an extra 150 tons per week.
In the summer of 1936 the site requirements for a new factory were drawn up.
The main priorities were that the establishment should not be vulnerable to
air attack; it should not be located in an industrial area, but sufficiently
close to a populated area to eventually be able to provide an adequate
workforce; the site should be reasonably close to a railway and to a main
road; it should be located on rough grassland with a gravel on sand subsoil
with good natural drainage and a slope of about 1 in 30 to provide maximum
safety in the highly dangerous nitroglycerine manufacturing and handling
areas. The higher part should not have an elevation of not less than 100 ft.
above the lowest part to limit the internal gradients. A capacious supply of
water was also required for use in the manufacturing processes (to
manufacture 150 tons of cordite per week the factory would need 3,000,000
gallons of drinking standard water per day).
During the critical time before the Munich crisis there were suggestions
that the site should be built as two independent factories and space the
individual buildings further apart to reduce the potential damage and
safeguarding production in the event of an aerial attack. Also, by
concentrating on one smaller unit immediately, production could begin
earlier. The commencement of war in September 1939 hastened the decision to
build a second unit. The earlier requirement for 500 acres of land soon
quadrupled to 2,000 acres.
In August 1937, four potential sites had been identified - two in
Gloucestershire, Aust (later to be the location of the Severn Bridge, the
toll booths and motorway service facility) and Berkley (a short distance
upstream of the Aust site). The two other proposed sites were near St.
Clears, Carmarthenshire. All four sites were rejected, due to the difficulty
in obtaining an adequate supply of suitable water. So the search continued,
and in September 1937 a second shortlist of sites had identified Caerwent,
Momnouthshire; Cowbridge, Glamorganshire; Laugharne, Carmarthenshire; and
Johnston, Pembrokeshire. Again there were problems with the water supply.
However, in discussions with the Great Western Railway it was pointed out
that in October 1879, during construction of the Severn Tunnel, workmen
accidentally tapped a fissure in the rock between Sudbrook camp and
Portskewett village. All of the local underground channels poured their
water into the tunnel, and within a short space of time almost every well,
spring and stream for about 5 miles from the tunnel became dry. The GWR
pumped out over 9 million gallons of water per day at Sudbrook at the
northern end of the Severn Tunnel, conveniently located only three miles
away from the proposed site at Caerwent. Even during the great drought of
1934 the lowest daily return was 9,112,00 gallons. The GWR used about 1.5
million gallons per day for routine locomotive work, so there was always a
guaranteed daily surplus of 7.5 million gallons. After careful consideration
of all potential sites it was decided that Caerwent was the best location
for the factory. In November 1937, after Cabinet approval, the machinery was
put into motion to secure the land by compulsory purchase. On December 8th
1938 the Admiralty announced that they "have decided to proceed
withoutfurther delay to construct a munitions works at Caerwent".
The total area acquired was 1,580 acres (639.38 hectares) of land, a total
of 1,163 acres were enclosed within the factory fence. The site is situated
north of the A48 Gloucester - Cardiff main road 4 miles west of Chepstow and
12 miles east of Newport. It is about 2 miles east-west, and 1.5 miles
north-south. It was, and indeed still is, one of the largest military sites
in Britain.
This area had previously consisted of rented smallholdings, owned by
Monmouthshire County Council. There was a small farm at Dinham and one large
farm at Lower Llanmelin. A number of the occupiers of the smallholdings were
elderly, and when given notice to quit, went into retirement. Most of the
land of Lower Llanmelin farm became Admiralty property and part of the
factory, but the farmhouse lies outside the factory fence and was leased
back to the farmer who continued to tend his land.
In the summer of 1939 the first surveys and marking out of the land had
begun. At this new site the Navy wished to change from their standard 2'6"
narrow gauge railway systems that were a common feature of Royal Navy
factories and adopt a modem comprehensive road transport system. It would
have to be worked out at an early stage, and be one of the first of the
civil engineering works to be started. Eventually over 29 miles of roadway
was laid down to serve the vast number of buildings within the
establishment. These roads were of tar macadam, and varied in width from ten
feet to 20 feet.
There was a need for a new single-line standard gauge rail line to be
constructed to link the factory to the London to Fishguard main lines at
Portskewett 2 miles to the south, and then on to the GWR marshalling yards
at Sevem Tunnel Junction. Two minor roads would have to be crossed, plus a
long-span bridge over the main Chepstow to Newport main road. A small
marshalling yard of 10 tracks, each about 200 yards long were laid out in
the south-east corner of the establishment, within the secure factory fence.
The GWR would bring in the rolling stock as far as these yards. From this
point they would be shunted all over the site by the RNPF tank engines.
The main contract for the building work was awarded in September 1939 to
Robert McAlpine & Sons. Due to the tense international political climate,
within a matter of only a few hours of signing the contract (and with no
agreed final costings) the first heavy construction machinery had arrived on
site. Work continued with a sense of increasing urgency, and a total
workforce of some 3,500 were employed in the construction. McAlpine
purchased and erected wooden huts from a Butlin & Warner holiday camp to
house the building labourers. The urgent need to complete the factory meant
that the Director of Navy Contracts granted permission to dispense with any
need for competitive tenders for machinery and plant provided that valuable
construction time would be saved.
The only known fatality at the factory occurred during the time of
construction. To the north of the factory is a point known as the "broken
bridge". This road crossing was a part of the internal roadway system. The
flyover bridge had very low headroom, and one day a worker was riding on the
back of one of the flatbed trucks, and stood up just as the truck went
underneath this bridge. The poor unfortunate worker was decapitated. As a
result of this accident the bridge was demolished. Locals believe that this
part of the site is haunted by the ghost of the headless workman.
In late 1940 and the early months of 1941 there was a steady transfer of
staff from Holton Heath to Caerwent. During this period the Admiralty
completed work on the pumping station adjacent to the GWR site at Sudbrook
and a 20" pipeline, to provide the water supply for the new factory at the
rate of 175,000 gallons per hour.
By the end of 1940 the Main Office block was complete, and in December of
that year the Unit 1 Sulphuric Acid Factory went into production, and so
acid mixing for the Nitrocellulose and Nitroglycerine manufacturing began.
Five months later, the Pressure Oxidation Plant for the manufacture of
Nitric Acid came on stream. In August 1941 the Nitrocellulose and
Nitroglycerine plants were operational and were soon working 24 hours a day
on a three-shift pattern. At the same time, Unit 2 of the factory was almost
completed, so RNPF Caerwent was now virtually operational.
A total of Ł4.7 million had been spent on buildings and roads, and Ł2.5
million on plant and equipment.
The main perimeter fence is 7.5 miles long, of 8 feet high steel
pallisading, and topped with three strands of barbed wire. At each change of
direction, a bastion is set into the angle, to enable the perimeter to be
protected during close-quarter attack. A similar fence divided the two
factory units. There were three main road entrances to the establishment, a
main rail entrance, and three "farmer's gates" on the northern fence, plus
one small entrance on the western fence. Two of the road entrances were
seldom used, the workforce used the gate located opposite the village of
Caerwent.
Both of the main factory units were subdivided into smaller units by wire
mesh fences. These were not intended to be a physical barrier, but indicated
a visible limit to the where special danger area rules and regulations
applied. Access to these areas was through gates that were manned by
searchers, authorised to check any individuals, entering or leaving, for
contraband. The staff changing rooms and clocking stations were located near
the entry points.
Close to the main entrance, near the bus parking area - but outside
perimeter fence - is an "air raid shelter farm". This collection of surface
shelters was built to afford protection to the workers in the event of an
air raid during shift changeover, when up to 2,000 people were entering or
leaving the factory. This area was also planned to accommodate a passenger
railway station for the workforce. However, legislation for the conveyance
of passengers would have demanded much higher standards than for carrying
freight. The chairs supporting the rails would need to be upgraded, a system
of signals established etc. Consequently the scheme was scaled-down and the
passenger facilities were never completed, so these shelters were never
used.
Mounds or traverses were erected around the Danger Buildings to prevent
explosive blasts from travelling horizontally to nearby buildings. However,
the isolated sites of the explosives factories and the regularly shaped
earthworks - always characteristic of an explosives factory - must have
presented a very considerable aerial camouflage problem. Under the guidance
of an army camouflage expert, a partial solution was to paint all of the
buildings in strips of black, green and buff to break up the rectangular
lines. Time has now taken its toll on the paint work and the rain has washed
away all traces, except for fragmentary remains on a wall of a building that
faces its neighbour only about five feet away. This wall would have been
impossible to observe from above, but the orders probably were to paint all
external walls - so all of the external walls were painted!
Caerwent is a reasonably level site and has gently sloping hills to the
north, which were suitable for the nitroglycerine plant. It was the usual
practice to place the NG plant on a slope so that the highly volatile liquid
could flow gently in lead gutters from one process to the next under the
influence of gravity, along lead-lined gutters (NG factories are often built
on rising ground in order to provide a fall from one process to the next.
Reference is often made to "NG hills", and workers in NG factories are known
as 'Hillmen').
Any explosive material entering or leaving the factory was taken to on of
two transfer sheds. During unloading the locomotive was uncoupled, and the
trucks pulled into the shed by electric capstan. Material would then be
unloaded by overhead crane and dispersed to surface holding areas or storage
sheds.
Acid Factories
Manufacturing of the necessary acids for the production of explosives was
carried out on site. The acid plants in both units were identical, and could
produce 50 tons of sulphur trioxide per week. Each acid factory had its own
double storey prefabricated reinforced concrete and engineering brick
sulphur store capable of holding 1,500 tons, with a high level rail line and
the sulphur storage bays beneath. The sulphur store in Unit 1 (south-eastern
corner of the site) was converted by the US Army to a magazine, but the
store in Unit 2 at the southwestern corner, despite being open to the
elements since the early 1960's still emits a very strong odour of sulphur.
A pair of rope mantlets at the back of the building were added when an
oilfired proving oven was installed for decontamination of material during
the process of rundown prior to closure of the factory.
Raw sulphur was trucked out of the store, into the weighing room and into
steam heated melters. The molten sulphur was then pumped to vertical
burners, the refractors. It was then filtered in a medium of silica brick
and a catalyst of vanadium pentoxide. The filter converted most of the
sulphur dioxide into sulphur trioxide, and the catalyst converted the
remaining sulphur dioxide.
The acid factories are situated at two localised high point in the factory.
Nitric Acid was made by the action of heat on a mixture of sulphuric acid
and sodium nitrate. contained in two stainless steel storage tanks each
capable of holding 34 tons of 60% acid.
Acids were then moved to the Concentration Plants. The function of these
plants was to concentrate the total output of 60% nitric acid to
concentrated nitric acid by extractive distillation, using steam heated
still columns, fed with concentrated sulphuric acid. After processing the
purity rose from 60% to 96%. It should be noted that acid in is pure, or
concentrated state is not as corrosive as acid that is dilute.
The acids were then stored in the acid "tank farm", of 7 mild steel tanks,
each capable of storing 200 tons of bulk liquid. Each tank was on a brick
plinth, in a brick-lined cylindrical compound. As a precaution against
damage or leakage, the whole acid farm was surrounded by an earth traverse.
The working conditions in the acids factories were - to say the very least -
unpleasant. The huge double-doors of the plants were always left open, even
in the depths of winter, probably because the cold was preferable to the
noxious gases given off by the manufacturing process. There was also a great
deal of noise emitted by the massive fans that drew the mixed gasses over
the catalyst. Unusually high numbers of workers in the acid factories
suffered from early loss of their teeth, probably as a result of breathing
in the sulphur dioxide fumes. However, at Holton Heath there were
compensations - due to trace elements of arsenic compounds in iron pyrites
the workers had beautiful complexions!
Nitrocellulose Plants
The Nitro-cellulose production units are particularly interesting, each unit
had a N/C section and were almost identical. Made up of four large
buildings, the manufacturing process buildings were connected by covered
asphalt corridors, 150 ft long, and wide enough for the passing of two
trucks used for transporting materials from one house to the next. To
conform with the Passive Defence Scheme the buildings were constructed with
flat reinforced concrete roofs, varying from 4" to 9" in thickness. This was
the recognised strength to withstand direct hits by 1 kilogram incendiary
bombs.
The nitrocellulose used in Naval propellant was manufactured from pure
cellulose received in the form of paper reels.
Rolls of paper were made up of alternating layers of plain and corrugated
papers at the Paper Preparation Room. The "Scrolls" were made of 16 lb.
double crown thickness paper (7 1/2" wide and 22" in diameter, weighing 8
3/4 lb.) and were produced by the 10 paper corrugating and scrolling
machines. Total output varied from 150 to 200 scrolls per hour. The room
could also accommodate 1,400 finished scrolls.
The doorway to the connecting corridor to the next stage in the process
formed the point of demarcation between the clean floor of the Paper
Preparation Room and the acid floor of the Nitrating House. Here, as in all
parts of the factory, all acid floors and walls exposed to acid fumes were
made of Accrington Nori brick.
At the Nitrating House they were placed in groups of four, each group being
known as a "Pan", and further bundled into groups of 4 Pans, making a "Set".
Therefore there were 16 Scrolls of paper in a Set. There were 10 Sets in the
room, making a total of 2,000 lb. of Nitro-cellulose being prepared at any
one time. The Scrolls were dipped in mixture of 63% Sulphuric Acid, 22%
Nitric Acid and 15% water. After dipping the paper was left to soak for a
further 2˝ hours. Fume extraction hoods covered the pans during the dipping
operation, but were removed after a top seal of water had been distributed
over the surface of the acid. Then the spent acids were displaced by the
action of pumping water in to the pans. These acids were run along gutters
and into denitration towers for further processing.
The Scrolls were then moved by hand-propelled trucks to the Vat House. The
2,000 lbs of material prepared in the Nitrating House filled one vat. Each
vat was 9'6" in diameter and 7'6" high, made of wood, barrel fashion with
constricting iron bands, and were lined with antimonial lead. There are 28
openings in the floor, therefore, during periods of maximum production,
there was storage space for a total capacity for 56,000 lbs of
Nitro-cellulose in this particular room.
The contents of the vats were boiled by the application of steam heating.
The sequence consisted of two 12 hour boils, followed by four 4 hour boils,
and finally a 1 hour boil. After cooling the liquid was drained off, the
Scrolls unloaded and moved to the final stage at the Pulping & Blending
House.
In this final room the process machinery included 7 beaters, 6 potchers, 4
blenders (with grit extractors), and hydroextractors.
The beaters were cast iron sloping troughs, about 16 ft long. Rolls of paper
from the vat house were pulped, in water, by a 4.6 ton roller driven at 180
r.p.m. for 4 hours. The resulting nitrocellulose pulp was pumped away
through a 4" valve.
Water soluble impurities and light insoluble material were removed bv the
Potchers, essentially large centrifugal separators, supported on stilts.
These 11 ft diameter, shallow conical, tile lined vessels could handle two
beater loads of material at a time. Washing was carried out by skimming off
the excess water from the top of the material after settling, utilising a
skimmer supported by a ball float.
The blending tanks were tile lined with pump injection circulation, and
could handle 5 vat loads in pulp form. The pulp slurry needed to be diluted
before passing on to the grit extractors. Capable of handling 500 lb., the
centrifugal hydroextractors were used for wringing the nitrocellulose.
Nitroglycerine Factories
At the planning stage for the factory it was decided that the nitration of
glycerine at Caerwent would be a continuous process. At the time of
construction the Schmid manufacturing method was comparatively new, this was
much cheaper and safer than any of the older batch methods.
During their time of occupation the US forces bulldozed the area and built
their munitions stores on the site of the NG factories. This would have been
a highly dangerous operation. Nitroglycerine is a highly volatile substance,
once made it does not break down to its constituent parts. Therefore any
spillage or trace elements on the ground could have disastrous consequences
if disturbed. As a result of the US construction, today there are almost no
remains of the two plants.
Each of the NG factories had Charge Houses, Nitration Houses, Wash Houses,
Wash Water Settling Houses, and Paste Mixing & Sheeting Houses. None of
these buildings survive,
However, what traces do remain reveal very interesting clues to the methods
employed at this point. Because of the volatile nature of the substance it
was always standard practice in NG factories to use gravity to move the
liquid from one part of the process to the next, with gently sloping
lead-lined canvas covered gutters. In 1931 at Holton Heath a minor explosion
in a NG soaked gutter spread to the adjacent production houses and resulted
in the deaths of ten NG Hillmen.
At Caerwent the use of NG guttering was minimised, but were still used for
passing the material to the wash houses and for carrying away wash waters to
the settling house. Rubber wheeled trolleys would be pushed by hand along
grooved asphalt runways. Although not a new idea (the same principle had
been employed at Holton Heath for many years) efficiency at Caerwent could
be improved by allowing two trolleys to pass by using a passing loop between
the process buildings. As far as can be ascertained, the one surviving
example at the north-east corner of the US magazine complex is the only one
in existence in any explosives factory world-wide
Asphalt used at this point was a hard wearing acid resistant gritless type
and was the same as that used for the floors of explosives magazines and any
other buildings where there was a possibility that acid may reach the floor.
The asphalt was prepared in sterile conditions offsite. Arrangements for the
supply included that the material was to be packed in strong closeboarded
cases to avoid the risk of any contact of grit during transit.
In the official document to contractors that set out the specifications for
construction, the section dealing with the laying down of the asphalt stated
that "All the workmen and supervising staff of the sub-contractor employed
on the site in connection with the laying of the asphalt must be British
subjects by birth and skilled in this class of work. Neutralised British
subjects are not to be employed on this work."
A similar document, outlining general specifications insisted that "All
materials are to be of British or Empire origin and manufacture unless
otherwise specified, and are to conform to British Standard Specifications
current at date of tendering where such are available."
Cordite Sections
The plant in both factory units could manufacture both solvent and
solventless cordite, and each were designed to produce 75 tons per week.
Most of the output was for gun cordite, some catapult charges and a small
amount of 3" rocket charges.
However, this was a time of great advances in cordite development and
production, and in 1939 the Armament Research Department introduced Picrite
(nitroguanidine) into cordite, in an attempt to reduce flash temperatures
and barrel wear. Picrite is a major component of flashless cordite and
produces massive quantities of nitrogen when the propellant bums and this
reaction has the effect of reducing barrel wear and muzzle flash. Further
developments at Caerwent resulted in this product being used exclusively as
the type of flashless gun propellant by the Royal Navy.
In an attempt to further reduce barrel wear it was decided to add petroleum
jelly to the Picrite. The theory was that it would lubricate the interior as
the projectile drew the vapours up the barrel. Unfortunately the additive
was instantly vaporised when the charge ignited. But all was not lost.
because the extra ingredient further reduced the flash temperature of the
cordite charge without affecting the propulsive properties, so indirectly
having the desired effect of reducing barrel wear.
Following the cessation of war with Germany production fell to 70 tons of
Solventless Cordite per week, and by the end of 1945, after the ending of
the conflict in the Far East, it dropped down to 17.5 tons per week.
During 1953 parts of the Cordite factories were converted for extrusion of
propellant for Guided Weapons booster motors. In 1955 experimental work
began on the propellant for the "Gosling" motors for the "Seaslug" missile
system. Caerwent also manufactured the "Magpie" motors for the "Firestreak"
air-to-air missile and the "Linnet" charges for "Red Top". Limited
experimental work was also carried out on the "Sealyham" rocket motors.
Tetryl Section
The Tetryl plant was designed to manufacture 6,000 lbs of Tetryl per week.
Production began in October 1941, but ceased in 1944 when the relatively
small Naval requirements were obtained from other sources.
Tetryl is a pale yellow crystalline material which was first prepared in
1877. Its use as an explosive dates from the early years of the twentieth
century and it has been widely used since the time of the Great War as an
intermediary, or 'booster', between the detonator and the main explosive
charge in shells and in bombs. Tetryl is known by chemists as 2,4,6
Trinitrophenylmethylnitramine, but in military parlance it becomes
Composition Exploding or even more succinctly, CE.
Laboratories
Raw materials used both directly and indirectly in the establishment were
tested at the RNPF laboratories. Frequent samples were taken from different
manufacturing stages of each type of product. Samples were also taken of
finished product, and complete analysis and stability tests undertaken.
After the closure of the Naval Ordnance Inspection Laboratory at Holton
Heath in 1947, the laboratories at Caerwent were responsible for the
inspection of Naval propellants and explosives during their service life.
All propellants undergo a degree of chemical deterioration, proportional to
the stability of the nitroglycerine and nitrocellulose. There were three
principal laboratories at RNPF Caerwent, the Main Laboratory, the Physics
Laboratory and the Acids Laboratory. All three were single story buildings
and were not duplicated, but other smaller, specialised laboratories were
under their control.
The Main Laboratory was equipped for general chemical analysis and would
oversee and control the composition of the propellant. It tested the raw
materials for propellant, such as glycerine, paper, acetone etc. It also
tested various products used in other support facilities at the factory,
such as coal, rubber, oils, clothing etc. From time to time these
laboratories would take samples of air in the workplaces, drinking water and
effluent, to ensure that they conformed to hygienic and legal
requirements.Experimental work was often undertaken, to devise new products
and to improve products and manufacturing processes. The Main Laboratory
also carried out some investigation for other establislunents, such as
testing of fireproof clothing, checking effluents from shell cleansing
plants, identification of moulds, dusts etc. This valuable work came in from
all over the world.
The Acids Laboratory was responsible for analysing acids at different stages
of production and mixing. It also controlled all of the acid plants and
would oversee the compositions of mixed acids used for nitrating glycerine
and cellulose. Samples of Nitrocellulose were also analysed at the Acids
Laboratory.
The Physics Laboratory carried out routine work such as inspection of the
calorific value, dimensional measurements and density of cordite, the
reflective index of glycerine (this test would ensure its suitability for
nitration), inspection of transformer oils etc.
Later all test firings of the rocket motors developed at Caerwent were under
the control of the Physics Laboratory.
As a part of the Naval Ordnance Inspection Department, the complex of
laboratories at RNPF Caerwent became the centre for all scientific work
dealing with the inspection of all explosives manufactured for the Royal
Navy.
In 1996 material came to light that suggested a section at the extreme north
of the establishment had been used by Whittle for early jet engine
experiments. While the location would have been secure and convenient for
the Gloucester based company, the idea of testing such a piece of equipment
in an explosives factory was approached with some degree of scepticism.
Field investigation of the site in question, and a search through the
surviving installation drawings in the administration buildings revealed the
actual purpose of the structures.
The reinforced concrete three-walled, open ended structure, close to the
'burning ground' was part of the Guided Weapons Scheme and was in fact the
static firing test bed for the rocket motors. Torpedo netting covered the
roof, as a precaution against accidental explosion. A subsequent
conversation with Mr. Charles W. Alexander - the former Chief Scientific
Officer - confirmed this, and he produced photographs of a test firing of a
Gosling motor.
Comprehensive First Aid facilities were distributed throughout the
establishment, the factory also had a ten bed hospital, with facilities for
performing emergency operations, staffed by a part-time Medical Officer, a
matron and two sisters. A dentist would attend once a week, to extract teeth
during working hours.
In September 1940 troops from the 5th Battalion, South Wales Borderers were
posted to guard the factory. The function of the guard was to prevent
sabotage and deal locally with enemy attack, pending the arrival of other
troops to be stationed in the district. The antiaircraft protection was
pathetically weak, being one Hotchiss and one Lewis gun.
At the end of the same year the 20th Light Anti-Aircraft Battery set up
camp, constructing 8 gun positions for 40mm Bofors guns. But the full
compliment never arrived, and only 4 sites were ever manned.
The following year 'D' Company of the 1st Monmouthshire Battalion Home Guard
was formed. This unit had a full-time Commanding Officer and a camp
consisting of a number of huts, later to become stores. The military guard
were gradually withdrawn and the Home Guard became responsible for defence
of the establishment.
Shortly after the 131 st Monmouthshire Home Guard Light Anti-Aircraft
Battery was formed from factory personnel. They became responsible for the
anti-aircraft defences during daylight hours. The Battery had a Battery
Office and a small camp - including a licensed bar. There were 16 gun
positions within the factory, with one 20mm Hispano gun and a Lewis gun at
each position. At night strict blackout conditions were observed. The
workforce put great faith in a night-time decoy site situated 3 miles to the
north of the factory at Coed Llifos.
Although there were no organised enemy raids against the factory some 15 to
20 incendiary bombs were dropped on a few occasions during 1940 and 194 1.
These only caused minor damage, with no injuries to personnel. Interestingly
the only serious damage caused was from one of the factories own anti
aircraft battery. Shells failed to explode in the air and came back down and
hit a corner of one of the buildings in Unit 1.
Scattered about the factory are 75 air raid shelters, each capable of
accommodating between 40 and 50 persons. These earth covered shelters with
diametrically opposed entrances are fabricated of brick and concrete
horseshoe shaped cross-section sections. All had water and electricity
supply and at least one Elsan lavatory. Several of these shelters still have
the seating rails, and almost all still have the original raised duck
boarding on the floor. Many key factory buildings had specially strengthened
rooms for protection of workers during air raids.
The First Aid and Decontamination Buildings, one in each factory unit, were
large buildings intended for the treatment of gas contaminated casualties.
They were divided down the middle into two identical halves, intended for
men and women. The discharge room was common to both. Each side provided for
a separate cleansing section for walking and stretcher casualties, leading
into a common first aid room. This section was ventilated by filtered air.
There were also four Gas Defence Stations, built as operational bases and
stores for gas decontamination parties. Equipped only for cleansing, there
were no first aid rooms, and no provision for separation of sexes.
After the war maintenance of passive defence systems was run down, but was
revived in the 1950's and a small Industrial Civil Defence Unit was
established. By this time the emphasis was not on gas decontamination, as it
had been superseded by the need for fallout decontamination. A limited
amount of training was carried out during working hours and there were links
with the Regional Civil Defence Headquarters based at Cardiff.
Early in the 1960's a parliamentary working party recommended that
propellants for the three branches of the armed services should be
concentrated at the Royal Ordnance Factory at Bishopton. The decision to
close RNPF Caerwent was announced on the 25th of March 1965. Production
continued during the following two year rundown phase, and so ended the
period when the Royal Navy had exclusive control over its propellant
manufacture and had built up a reputation that was second-to-none for
quality and safety standards.
Buildings used for the production, proving and handling of explosives were
thoroughly cleaned, then "sterilised" with flame guns. Many buildings that
were known to have been impregnated with explosive material were burnt out
by building large wood and oil fires inside them. Contaminated buildings
made of wood were simply set alight. By the end of June 1968, all
decontamination of buildings and machinery had been completed.
During the rundown period some attempts were made to try and attract
industry to Caerwent, with little success. In 1967 President Charles
DeGaulle invited NATO forces to leave France as his country had decided to
withdraw from the military structure of NATO. The US Army, on the lookout
for new homes was offered Caerwent as one of the ten sites in the UK they
eventually came to occupy. On the 22nd of November it was announced that the
site would be made available for the storage of conventional ammunition by
the United States Army's 47th Area Support Group Reserve Storage Activity,
supported by a Royal Air Force Liaison Party. The US Army spent over Ł4
million constructing 300 magazines and converting some of the former RNPF
structures to conform to the required specification. The material stored
included small arms ammunition, artillery shells (up to 8"), anti-tank
mines, grenades, flares and multiple-launch rocket systems.
At its height Caerwent was the largest ammunition supply depot in Western
Europe, storing over 80,000 tonnes of conventional munitions. In 1990 RSA
Caerwent shipped 12,000 tons of ammunition to the Middle East and played a
critical part in Operation Desert Shield and Desert Storm.
Following the change in the political climate in Europe and subsequent
scaling down of operations, the US Army announced it was to close down their
storage operations at the establishment in June 1992. Over 60,000 tonnes of
munitions was moved out over a period of less than ten months, and completed
their clearout two weeks ahead of schedule. The last batch was removed by
train on the 19th of July 1993. The formal closure ceremony took place on
the 20th of August 1993, ending another chapter in Caerwent's history.
The site has recently been used for military training and public order
training by various police forces. A few local farmers are allowed to graze
their livestock on the convenient areas of pasture that separate the former
factory buildings.
A beneficial side effect of the semi-dormant state of the establishment is
that the wildlife is now thriving. Specialists have recorded 30 species of
fungi, 24 species of butterflies, 70 species of birds and 20 species of
mammals.
From the time the US forces left, the future of the factory was in doubt. It
was even suggested that the site could be used to accommodate 4,000 houses -
a massive private investment. But local opposition meant that the idea had
to be revised. In the Autumn of 1997 its future was finally decided. RNPF
Caerwent is to be used for "Backdoor" training by the army regiments based
in Wales.
During its years of production, the RNPF never once failed to supply the
Royal Navy with its propellant requirements. In 1942, at the height of the
Battle of the Atlantic, the workforce even managed to increase production
from 150 to 250 tons of cordite per week. In 26 years of manufacturing
propellant and 25 years of munitions storage there were no incidents of
major injury of any description, a safety record that is second to none. It
was, without doubt, the most dangerous place of work in Wales. The extremely
low accident,rate at the site underlines how a large number of people could
work together, and the routine efficiency was a textbook example of team
work.
Acknowledgements
Firstly, 1 must extend my heartfelt thanks to Mr. C.W. Alexander, who worked
at Holton Heath from 1928 until he was transferred to Caerwent in 1940, and
subsequently became the Chief Scientific Officer, and was employed as such
until closure in the late 1960's. Mrs. J. Moulton, the former secretary to
the Commanding Officer has also been an invaluable source for material
relating to the time of US Army occupation. Mr. W.D. Cocroft of the Royal
Commission on Ancient Monuments of England was of great assistance during
the early stage of my research and interpretation of the factory buildings,
and also pointed me in the direction of further research material. The
constant assistance and encouragement from the officers of the Defence Land
Agents based at Brecon and the security staff at Caerwent have always been
deeply appreciated, and they have always allowed access to this magnificent
site, often at very short notice. Last, but not by any means the least, the
staff and team of volunteers from the Defence of Britain Project.
!!!!! Thanks so much for your comments! 
